Question

3. Determine o valor de x que satisfaz as equações abaixo:
a) 3(x - 12) = 10x - 15
b) 9 + 3(2x - 1) = 4x + 7​

Answer 1

$A) 3(x - 12) = 10x - 15\\3x-36=10x-15\\10x-3x=-36+15\\7x=-21\\x=\frac{-21}{7}\\ x=-3\\\\B)9 + 3(2x - 1) = 4x + 7\\9+6x-3=4x+7\\6x-4x=7-9+3\\2x=1\\x=\frac{1}{2}$

Answer 2

a)

$3.(x-12)=10x-15 \\ 3x-36=10x-15$

$10x-3x=15-36 \\ 7x=-21 \\ x=-\frac{21}{7} \\ x=-3$

b)

$9+3(2x-1)=4x+7 \\ 9+6x-3=4x+7 \\ 6x-4x=7+3-9$

$2x=1 \\ x=\frac{1}{2}$