Question 34254
I will help you solve one and you solve the others.
This is called solving equations by substitution.

x+y=25 and y=4x. Hold on we know that y=4x plug that into the first equation.
x+4x=25==>5x=25==>x=5.

Plug in 5 into one of the equations in order to get y. 5(4)=20.
Use this process for the remaining questions.