Question

Determine os valores de x nas equações

B- (x+3).(2x+10)=0

Answer 1

$B- (x+3).(2x+10)=0\\\\\\ 2 x^{2} +10x+6x+30=0\to\\\\ 2x^{2} +16x+30=0\\\\ a=2;b=16;c=30\\\\\\ \Delta=b^2-4ac\to \Delta=16^2-4*2*30\to \Delta=256-240\to \Delta= 16\\\\\\ x' \neq x''\\\\\\ x= \frac{-b\pm \sqrt{\Delta} }{2a} \to x= \frac{-16\pm\sqrt{16} }{2*2} \to x= \frac{-16\pm 4}{4} \to \\\\\\ x'= \frac{-16+ 4}{4} \to x'= \frac{-12}{4} \to x'=-3\\\\\\ x''= \frac{-16-4}{4} \to x''= \frac{-20}{4} \to x''=-5\\\\\\\ S=(-5;-3)$


Espero ter ajudado...

Answer 2

(x + 3).2x + 10) = 0
2x² + 10x + 6x + 30 = 0
2x² + 16x + 30 = 0 (:2)
x² + 8x + 15 = 0

a = 1; b = 8; c = 15

Δ = b² - 4ac
Δ = 8² - 4.1.15
Δ = 64 - 60
Δ = 4

x = - b +/- √Δ  = - 8 +/- √4        
             2a                2.1

x = - 8 + 2  = - 6/2 = - 3
           2

x = - 8 - 2  = - 10/2 = - 5
          2

R.: x = - 3 e x = - 5