ABC26GN1066 · Simplification

Subject: General Aptitude · Chapter: Simplification · Exam: 2006 · Marks: · Difficulty:

If $x^{2}-7 x=-12$, what is the value of $x$ ?

(a)- 3 or - 4

(b)3 or 4

(c)3 or - 4

(d)Cannot be determined

(e)None of these

Answer

Answer (as printed): B

Explanation

$x^{2}-7 x=-12 \Leftrightarrow x^{2}-7 x+12=0$ $$\begin{aligned} & \Leftrightarrow x^{2}-3 x-4 x+12=0 \\ & \Leftrightarrow x(x-3)-4(x-3)=0 \\ & \Leftrightarrow(x-3)(x-4)=0 \\ & \Leftrightarrow x=3 \text { or } x=4 \end{aligned}$$

Explanation as extracted from the printed page; notation may be imperfect.

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