If x4 = 7, what is the value of x2 + 1? | SAT Linear equations in one variable Question, Answer Explained

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Math · AlgebraEasy

If $\frac{x}{4} = 7$ , what is the value of $\frac{x}{2} + 1$ ?

$14$

$15$

$28$

$29$

Show answer and explanation

Answer: B

Multiply both sides by $4$ : $x = 28$ . Then $\frac{x}{2} + 1 = \frac{28}{2} + 1 = 14 + 1 = 15$ . You can also see that $\frac{x}{2}$ is twice $\frac{x}{4}$ , so $\frac{x}{2} = 14$ .

Choice A is the value of $\frac{x}{2}$ , but the question asks for $\frac{x}{2} + 1$ .

Why the other choices are wrong

A. 14 is the value of x/2. The expression also adds 1.
C. 28 is the value of x, not of x/2 + 1.
D. This adds 1 to x instead of to x/2.

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