Explicație pas cu pas:
[tex]4 = ( - 1) \times ( - 2) \times 2[/tex]
[tex]16 = 1 \times 2 \times 8[/tex]
[tex] - 17 = 1 \times ( - 1) \times 17[/tex]
[tex] - 1 = ( - 1) \times ( - 1) \times ( - 1)[/tex]
.
a = -4; b + c = -15
ab + ac = a(b + c) = -4(-15) = 4×15 = 69
a = -11; b - c = -12
ab - ac = a(b - c) = -11(-12) = 11×12 = 132
.
ab + ac = -216; b + c = 72
a(b + c) = -216
a×72 = -216
a = -216÷72 => a = -3
