How do you solve this system of equations: y+ 3= x and 3x + 4y = 16?

2 Answers
Jun 9, 2018

x=4,y=1

Explanation:

Writing y+3 for x in the second equation

3(y+3)+4y=16
expanding
3y+9+4y=16
so 7y=7
y=1

so
x=4

Aug 9, 2018

y=1
x=4

Explanation:

The easiest way here is by substitution. We know what x is, because of the first equation so simply take what x is and substitute it for x in the second equation like so:

3(y+3) +4y = 16

Distribute the 3

3y + 9 +4y = 16

Combine like terms

7y+ 9= 16

solve for y by subtracting 9 from both sides then dividing both sides by 7:

y=1

plug 1 in for y into either of your original equations and solve for x

x=4