Question

2( x quadrado - 3 ) + 3(4x-5)

Answer 1

2(x² -3) +3(4x -5)
2x² -6 +12x -15
2x² + 12x -21 = 0

Δ = b² -4ac
Δ = 12² -4.2.(-21)
Δ = 144 + 168
Δ = 312

x = - b +- √Δ /2a
x = -12 +- 17,66/4
$x^{I}$ = -3 + 17,66 = -14,66
$x^{II}$ = -3 - 17,66  = -20,66