Question

(2×-4).(×+3)

Delta!!Me ajudeem

Answer 1

$(2x - 4)(x + 3) = 2x \times x + 2x \times 3 - 4 x - 4 \times 3 = \\ =2 {x}^{2} - 6x - 4x - 12 = \\ = 2 {x}^{2} - 10x - 12$

$2 x^{2} -10x-12=0 \\ x^{2} -5x-6=0$

Δ$= (-5)^{2} -4.1.(-6)=25+24=49$


$x= \frac{5+ \sqrt{49} }{2} = \frac{5+7}{2} = \frac{12}{2} =6 \\ \\ x= \frac{5- \sqrt{49} } {2} = \frac{5-7}{2} = \frac{-2}{2} =-1$

S = {-1, 6}