Question

$2 x^{2} -7x=15$

Answer 1

$2x^{2} -7x-15 = 0$

Δ = $b^{2} -4ac$
Δ = $(-7) ^{2} -4.2.(-15)$ = 49 + 120 = 169 

x' = $\frac{-(-7)+ \sqrt{169} }{2.2} = \frac{7+13}{4} = 20/4 = 5$

x'' = $\frac{-(-7)- \sqrt{169} }{2.2} = \frac{7-13}{4} = -6/4 = -3/2$