Question

how can I solve this system of linear equations by substitution 3x-2y=9 and y=2x-7

Answer 1

y=2x-7
therfor we can SUBSITUTE 2x-7 for y whereever we see y in the other equation

3x-2(2x-7)=9
3x-4x+14=9
-x+14=9
minus 14 both sides
-x=-5
mulitly -1
x=5

sub back

y=2x-7
y=2(5)-7
y=10-7
y=3

(5,3)