Question

b(x+1).(x-2)=-7x-10

Answer 1

(x + 1).(x - 2) = - 7x - 10
x² - 2x + x - 2 = - 7x - 10
x² - x - 2 = - 7x - 10
x² - x + 7x - 2 + 10 = 0
x² + 6x + 8 = 0

a = 1; b = 6; c = - 10

Δ = b²  -4ac
Δ = 6² - 4.1.(-10)
Δ = 36 - 4.(-10)
Δ = 36 + 40
Δ = 76
√Δ = √76 = √4.√19 = 2√19

x = - b +/- √Δ
         2a

x = - 6 +/- √76
           2.1

x' = - 6 + 2√19 = - 3 + √19
            2

x" = - 6 - 2√19  = - 3 - √19
             2

R.: x = - 3 + √19 e x = - 3 - √19