Question

preciso das seguintes resposta:(x+4).(x-4) e (x+8). (x+7)

Answer 1

(x+4).(x-4)=0
x²-4x+4x-16=0
x²-16=0
x²=0+16
x²=16
x=√16
x= 4

(x+8).(x+7)=0
x²+7x+8x+56=0
x²+15x+56=0
a=1
b=15
c=56

Δ= b²-4ac
Δ= 15²-4.1.56
Δ= 225-224
Δ= 1

x= -b±√Δ/2a
x= -15±√1/2.1
x= -15±1/2
x¹= -15 + 1 /2 = -14/2 = -7
x²= -15 - 1 /2 = -16/2 = -8