Question

como resolver : (4-x)(2x+1)=10

Answer 1

(4-x)(2x+1) = 10
8x + 4 -2x - x = 10
Soma/subtraia termos semelhantes
5x + 4 = 10
5x = 10 - 4
5x = 6
x = 6/5

Espero ter ajudado!

Answer 2

(4-x)(2x+1)=10

8x + 4 - 2x² - x = 10

- 2x² + 7x - 6 = 0

Δ = b² - 4ac

Δ = 7² - 4 ×(- 2) ×(- 6)

Δ = 49 - 48

Δ = 1

x = -b / 2a

x' = - 7 + 1 / 2 × (- 2)

     - 6 / - 4

        3 / 2

x" = - 7 - 1 / 2 × (- 2)

       - 8 / - 4

        2