Question

b) x² + 3x - 72 = 0
d) x2 - x - 56=0
f) x² + 3x - 154 = 0​

Answer 1

Respuesta:

b) x1 = -3 -3√33/2, x2 = -3+3√33/2

d)  x = 56

f) x = -14, x2 = 11

Explicación paso a paso:

b) x² + 3x - 72 = 0

x = -3 ± √3² - 4×1×(-72)/2×1

x = -3 ± √3² - 4 × (-72)/2×1 → x = -3 ± √3² - 4 × (-72)/2 →  x = -3 ± √9 - 4 × (-72)/2 →  x = -3 ± √9 + 288/2

x = -3 ± √297/2

x = -3 ± 3√33/2

x = -3 + 3√33/2

x = -3 - 3√33/2

Resultado final

x1 = -3 - 3√33/2,  x2 = -3 + 3√33/2

d) x2 - x - 56=0

2x - x - 56 = 0

x - 56 = 0

Resultado final

x = 56

f) x² + 3x - 154 = 0

x² + 14x - 11x - 154 = 0

Xx (x + 14) - 11x - 154 = 0 → X x (x + 14) - 11(x + 14) = 0

(x + 14)×(x - 11) = 0

↓

x + 14 = 0

x - 11 = 0

↓

x = -14

x - 11 = 0 → x = 11

Resultado final

x1 = -14, x2 = 11