Question

y+90=4y+15 qual e o valor de y

Answer 1

$y + 90 = 4y + 15 \\ y - 4y = - 90 + 15 \\ 3y = - 75 \\ y = - 75 \div -3 \\ y = 25$

Answer 2

$y + 90 = 4y + 15 \\ y - 4y = 15 - 90 \\ - 3y = - 75( - 1) \\ 3y = 75 \\ y = \frac{75}{3} \\ y = 25$