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Algebraic Manipulations: all problems

Focus mode: every practice problem from the chapter, one after another.

0 / 25 solved

Problem 12.6.1

AMC 10

Assuming a≠3a \neq 3, b≠4b \neq 4, and c≠5c \neq 5, what is the value in simplest form of the following expression?

a−35−c⋅b−43−a⋅c−54−b\frac{a-3}{5-c} \cdot \frac{b-4}{3-a} \cdot \frac{c-5}{4-b}

Problem 12.6.2

AMC 10

Suppose that xx and yy are nonzero real numbers such that 3x+yx−3y=−2\frac{3x+y}{x-3y} = -2. What is the value of x+3y3x−y\frac{x+3y}{3x-y}?

Problem 12.6.3

AMC 10

Real numbers aa and bb satisfy the equations 3a=81b+23^a = 81^{b+2} and 125b=5a−3125^b = 5^{a-3}. What is abab?

Problem 12.6.4

AMC 10

Let a+1=b+2=c+3=d+4=a+b+c+d+5a + 1 = b + 2 = c + 3 = d + 4 = a + b + c + d + 5. What is a+b+c+da + b + c + d?

5 equations: a − k = −1; b − k = −2; c − k = −3; d − k = −4; a + b + c + d − k = −5

multiply by2

Goal: a+b+c+da + b + c + d

5 rows. Tap rows to select them.

Problem 12.6.5

AMC 10

If y+4=(x−2)2y + 4 = (x - 2)^2, x+4=(y−2)2x + 4 = (y - 2)^2, and x≠yx \neq y, what is the value of x2+y2x^2 + y^2?

Problem 12.6.6

AMC 10

Real numbers xx and yy satisfy x+y=4x + y = 4 and x⋅y=−2x \cdot y = -2. What is the value of

x+x3y2+y3x2+y?x + \frac{x^3}{y^2} + \frac{y^3}{x^2} + y?

Problem 12.6.7

AMC 10

For what value xx does 10x⋅1002x=1000510^{x} \cdot 100^{2x} = 1000^{5}?

Problem 12.6.8

AMC 12

Given that xx and yy are distinct nonzero real numbers such that x+2x=y+2yx + \frac{2}{x} = y + \frac{2}{y}, what is xyxy?

Problem 12.6.9

AMC 10

Suppose that real number xx satisfies

49−x2−25−x2=3.\sqrt{49 - x^2} - \sqrt{25 - x^2} = 3.

What is the value of 49−x2+25−x2\sqrt{49 - x^2} + \sqrt{25 - x^2}?

Problem 12.6.10

AMC 10

Two non-zero real numbers, aa and bb, satisfy ab=a−bab = a - b. Which of the following is a possible value of ab+ba−ab\frac{a}{b} + \frac{b}{a} - ab?

Click a choice or type its letter (A–E).

Problem 12.6.11

AMC 10

Real numbers xx and yy satisfy the equation x2+y2=10x−6y−34x^2 + y^2 = 10x - 6y - 34. What is x+yx + y?

x² − 10x = (x − 5)² − 25; at x = 6: -24

x6
b-10
62−10⋅6=1−25=−246^2 - 10 \cdot 6 = 1 - 25 = -24
x2−10x=(x−5)2−25x^2 - 10x = (x - 5)^2 - 25

x² − 10x = (x − 5)² − 25; at x = 6: -24

Problem 12.6.12(additional)

If x+1x=4x + \frac{1}{x} = 4, then what is the value of x8+1x8x^8 + \frac{1}{x^8}?

Problem 12.6.13(additional)

MATHCOUNTS

If (a−1a)2=4\left(a - \frac{1}{a}\right)^2 = 4, what is the absolute value of (a3−1a3)\left(a^3 - \frac{1}{a^3}\right)?

Problem 12.6.14(additional)

AMC 10

Which of the following is equivalent to x1−x−1x\sqrt{\dfrac{x}{1 - \frac{x-1}{x}}} when x<0x < 0?

Click a choice or type its letter (A–E).

Problem 12.6.15(additional)

AIME

Find x2+y2x^2 + y^2 if xx and yy are positive integers such that

xy+x+y=71,x2y+xy2=880.xy + x + y = 71, \qquad x^2y + xy^2 = 880.

Problem 12.6.16(additional)

AIME

Let x1≤x2≤⋯≤x100x_1 \leq x_2 \leq \cdots \leq x_{100} be real numbers such that ∣x1∣+∣x2∣+⋯+∣x100∣=1|x_1| + |x_2| + \cdots + |x_{100}| = 1 and x1+x2+⋯+x100=0x_1 + x_2 + \cdots + x_{100} = 0. Among all such 100-tuples of numbers, the greatest value that x76−x16x_{76} - x_{16} can achieve is mn\frac{m}{n}, where mm and nn are relatively prime positive integers. Find m+nm + n.

Problem 12.6.17(additional)

AIME

Suppose that xx, yy, and zz are three positive numbers that satisfy the equations xyz=1xyz = 1, x+1z=5x + \frac{1}{z} = 5, and y+1x=29y + \frac{1}{x} = 29. Then z+1y=mnz + \frac{1}{y} = \frac{m}{n}, where mm and nn are relatively prime positive integers. Find m+nm + n.

Problem 12.6.18(additional)

AIME

Find ax5+by5ax^5 + by^5 if the real numbers aa, bb, xx, and yy satisfy the equations

ax+by=3,ax2+by2=7,ax3+by3=16,ax4+by4=42.\begin{aligned} ax + by &= 3, \\ ax^2 + by^2 &= 7, \\ ax^3 + by^3 &= 16, \\ ax^4 + by^4 &= 42. \end{aligned}

s_k = -14·s_(k−1) + 38·s_(k−2): s_5 = 20

sk=axk+byk⇒sk=p sk−1+q sk−2s_k = a x^k + b y^k \quad\Rightarrow\quad s_k = p\,s_{k-1} + q\,s_{k-2}
  1. s1=ax1+by1s_{1} = ax^{1} + by^{1}33given
  2. s2=ax2+by2s_{2} = ax^{2} + by^{2}77given
  3. s3=ax3+by3s_{3} = ax^{3} + by^{3}1616given
  4. s4=ax4+by4s_{4} = ax^{4} + by^{4}4242given
  5. s5=ax5+by5s_{5} = ax^{5} + by^{5}?
Goal: s5=ax5+by5s_{5} = ax^{5} + by^{5}

Known values 3, 7, 16, 42. Find p and q.

Fit sₖ = p·sₖ₋₁ + q·sₖ₋₂ to the four given values, then run it forward. (Written this way, p = x + y and q = −xy.)

Problem 12.6.19(additional)

AIME

The equation 2333x−2+2111x+2=2222x+1+12^{333x-2} + 2^{111x+2} = 2^{222x+1} + 1 has three real roots. Given that their sum is m/nm/n where mm and nn are relatively prime positive integers, find m+nm + n.

Problem 12.6.20(additional)

AIME

What is the product of the real roots of the equation x2+18x+30=2x2+18x+45x^2 + 18x + 30 = 2\sqrt{x^2 + 18x + 45}?

Problem 12.6.21(additional)

AIME

Find A2A^2, where AA is the sum of the absolute values of all roots of the following equation:

x=19+9119+9119+9119+9119+91xx = \sqrt{19} + \cfrac{91}{\sqrt{19} + \cfrac{91}{\sqrt{19} + \cfrac{91}{\sqrt{19} + \cfrac{91}{\sqrt{19} + \cfrac{91}{x}}}}}

Problem 12.6.22(additional)

AIMEChallenge

Let aa, bb, cc, and dd be real numbers that satisfy the system of equations

a+b=−3,ab+bc+ca=−4,abc+bcd+cda+dab=14,abcd=30.\begin{aligned} a + b &= -3, \\ ab + bc + ca &= -4, \\ abc + bcd + cda + dab &= 14, \\ abcd &= 30. \end{aligned}

There exist relatively prime positive integers mm and nn such that

a2+b2+c2+d2=mn.a^2 + b^2 + c^2 + d^2 = \frac{m}{n}.

Find m+nm + n.

Problem 12.6.23(additional)

AIMEChallenge

Let mm be the largest real solution to the equation

3x−3+5x−5+17x−17+19x−19=x2−11x−4.\frac{3}{x-3} + \frac{5}{x-5} + \frac{17}{x-17} + \frac{19}{x-19} = x^2 - 11x - 4.

There are positive integers aa, bb, and cc such that m=a+b+cm = a + \sqrt{b + \sqrt{c}}. Find a+b+ca + b + c.

Problem 12.6.24(additional)

AIMEChallenge

Let xx and yy be real numbers satisfying x4y5+y4x5=810x^4y^5 + y^4x^5 = 810 and x3y6+y3x6=945x^3y^6 + y^3x^6 = 945. Evaluate 2x3+(xy)3+2y32x^3 + (xy)^3 + 2y^3.

Problem 12.6.25(additional)

AIMEChallenge

The equation 2000x6+100x5+10x3+x−2=02000x^6 + 100x^5 + 10x^3 + x - 2 = 0 has exactly two real roots, one of which is m+nr\frac{m + \sqrt{n}}{r}, where mm, nn and rr are integers, mm and rr are relatively prime, and r>0r > 0. Find m+n+rm + n + r.