Question

b) 3(x + 2) = 15

c) –2(y + 4) = -10 + 9(y – 1)

d) 4x – 7 = 2x – 8

Alguém sabe responder essas ?

Answer 1

Resposta:

b) x = 3

c) y = 1

d) x = -1/2

Explicação passo-a-passo:

b)

$3(x+2)=15\\\\3\;.\;x+3\;.\;2=15\\\\3x+6=15\\\\3x=15-6\\\\3x=9\\\\x=\dfrac{9}{3}\\\\\boxed{x=3}$

c)

$-2(y+4)=-10+9(y-1)\\\\-2\;.\;y+(-2\;.\;4)=-10+9\;.\;y+(9\;.\;-1)\\\\-2y-8=-10+9y-9\\\\-2y-9y=-10-9+8\\\\-11y=-19+8\\\\-11y=-11\\\\y=\dfrac{-11}{-11}\\\\\boxed{y=1}$

d)

$4x-7=2x-8\\\\4x-2x=-8+7\\\\2x=-1\\\\x=\dfrac{-1}{2}\\\\\boxed{x=-\dfrac{1}{2}}$