If x²-7 x=-12, what is the value of x ? · ABC26GN1066
Subject: General Aptitude · Chapter: Simplification · Exam: C.E.T. 2006
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
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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