3X = 15 + 5y does not have a single answer. The answer forms a line on the Cartesian plane.
In order to reach a single solution you must have two equations when there are two unknowns.
4x+7-3x = 15 4x-3x = 15-7 x = 8
solve -3x-3y=-15
3x plus 5 equals 20: 3x + 5 = 20 3x + 5 - 5 = 20 - 5 3x = 15 3x/3 = 15/3 x = 5
-3x + 5 = 20 -3x = 15 x = -5
5x+y=-7 3x+y=15 8=D
no
(0,7)
3
x = -8
23
x=7
x2 plus 3x plus 3 is equals to 0 can be solved by getting the roots.