Question

Em forma de susbstituiçao como resolvo: x=y-4 2x+y=70 ???

Answer 1

$x=y-4 \\ \\2x+y=70 \\2.(y-4)+y=70 \\2y-8+y=70 \\2y+y=70+8 \\3y=78 \\y= \frac{78}{3} \\y=26 \\ \\x=y-4 \\x=26-4 \\x=22$