Question what-i

2.2 Nonlinear Equations in One Variable - Quadratic solving (factoring, quadratic formula, completing square)
0:00

the fraction with numerator 2 times, open parenthesis, x plus 1, close parenthesis, and denominator x plus 5, end fraction, equals 1 minus the fraction with numerator 1, and denominator x plus 5, end fraction

What is the solution to the equation above?

A.

0

B.

2

C.

3

D.

5

What is the solution to the equation above?

Hard-difficulty · SAT Math · Nonlinear Equations in One Variable — Quadratic solving (factoring, quadratic formula, completing square). Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.

Answer explanation

Choice B is correct. Since the fraction with numerator x plus 5, and denominator x plus 5, end fraction is equivalent to 1, the right-hand side of the given equation can be rewritten as the fraction with numerator x plus 5, and denominator x plus 5, end fraction, minus, the fraction 1 over, x plus 5, end fraction , or the fraction with numerator x plus 4, and denominator x plus 5, end fraction. Since the left- and right-hand sides of the equation the fraction with numerator 2 times, open parenthesis, x plus 1, close parenthesis, and denominator x plus 5, end fraction, equals, the fraction with numerator x plus 4, and denominator x plus 5, end fraction have the same denominator, it follows that 2 times, open parenthesis, x plus 1, close parenthesis, equals x plus 4. Applying the distributive property of multipliion to the expression 2 times, open parenthesis, x plus 1, close parenthesis yields 2 times x, plus, 2 times 1, or 2 x plus 2. Therefore, 2 x plus 2, equals, x plus 4. Subtracting x and 2 from both sides of this equation yields x equals 2.

Choices A, C, and D are incorrect. If x equals 0, then the fraction with numerator 2 times, open parenthesis, 0 plus 1, close parenthesis, and denominator 0 plus 5, end fraction, equals 1 minus, the fraction with numerator 1, and denominator 0 plus 5, end fraction. This can be rewritten as 2 over 5, equals 4 over 5, which is a false statement. Therefore, 0 isn’t a solution to the given equation. Substituting 3 and 5 into the given equation yields similarly false statements.