Use the substitution method to solve the system of equations.

4x – y = 4
x + 4y = 18

Question

Use the substitution method to solve the system of equations.

4x – y = 4
x + 4y = 18

anonymous · Answer

(1, 4) /
   (4, 2) /
   (4, 1) /
   (2, 4)

myininaya · Answer

solve the first for either y or x 
say we solve for y
now plug that y into the second equation where there is y and solve that equation for x
and then go back to the first equation that you solved for y and plug the x you just found wherever there is an x

myininaya · Answer

$$-y=4-4x => y=-4+4x$$ 
see i solved the first equation for y

myininaya · Answer

now plug this in wherever you have a y in the equation and solve for x

myininaya · Answer

$$x+4(-4+4x)=18$$
solve this for x

myininaya · Answer

You know it would be best not to post the same question twice.  Thanks.

anonymous · Answer

after solving for x, we get x=2