What value of x satisfies the equation 2x + 3 = 9? | SAT Nonlinear equations in one variable and systems of equations in two variables Question, Answer Explained

Math · Advanced MathEasy

What value of $x$ satisfies the equation $\sqrt{2x} + 3 = 9$ ?

$3$

$18$

$36$

$72$

Show answer and explanation

Answer: B

Subtract $3$ from both sides: $\sqrt{2x} = 6$ . Square both sides: $2x = 36$ . Divide by $2$ : $x = 18$ . Check: $\sqrt{36} + 3 = 9$ .

Choice C is the value of $2x$ , not $x$ .

Why the other choices are wrong

A. This divides 6 by 2 without squaring. Since √(2x) = 6, square both sides first to get 2x = 36.
C. 36 is the value of 2x. Divide by 2 to get x.
D. This adds 3 to 9 instead of subtracting, so it solves √(2x) = 12.

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