Question

use bhaskara x(x+11)+2(x+21)igual a 0

Answer 1

x(x+11)+2(x+21)=0
$x^{2} +11x+2x+42=0 \\ x^2+13x+42=0$

Δ=$b^2-4.a.c$
Δ=$13^2-4.1.42$
Δ=$169-168$
Δ=1

x'=$\frac{-b+- \sqrt{D} }{2.a}$
x'=$\frac{-13+- \sqrt{1} }{2.1}$
x'=$\frac{-13+1}{2}$
x'=$\frac{-12}{2}$
x'=-6

x''=$\frac{-13- \sqrt{1} }{2.1}$
x''=$\frac{-14}{2}$
x''=-7