How do you solve #3x+2y=27# and #x=y+4# using substitution?
1 Answer
Mar 5, 2016
x = 7 , y = 3
Explanation:
One of the equations x = y + 4 , gives x in terms of y.
This means it can be substituted directly into 3x + 2y = 27.
hence : 3( y + 4 ) + 2y = 27 . We now have an equation in 1 variable.
expanding brackets : 3y + 12 + 2y = 27
collecting y terms on left and numbers on right gives:
5y = 27 - 12 → 5y = 15 → y = 3
now x = y+4 → x = 3 + 4 = 7
