How to solve 4y=x 3x - y=70 using substitution

X = 4y

3x - y = 70

substitute the x in the second equation with the other half of the first equation.

3 (4y) - y = 70

12y - y = 70

11y = 70

y = 6.36 repeating, or 6 4/11

now use this to solve first equation

x = 4 (6 4/11)

x = 25.45 repeating

done