Question

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Answer 1

#17. $x^{2} +x-12=60$
        $x^{2} +x-12-60=0$
        $x^{2} +x-72=0 \\ \\ x^{2} -8x+9x-72=0 \\ \\ ( x^{2} -8x)+(9x-72)=0 \\ \\ x(x-8)+9(x-8)=0 \\ \\ (x+9)(x-8)=0$
        x + 9 = 0 or x - 8 = 0
        x = -9 or x = 8