If the first equation is multiplied by 3 and then the equations are added, the result is 3x + y = 3 x - 3y = -2 a) 10x = 11 b) 10x = 7 c) 8x = 7

To practice, what if the two are added now? lets add one term at a time. first the x terms. 3x+x= 4x. then y+-3y=-2y. finally 3+-2=1. now putting them together we get 4x-2y=1.

multiplying the first equation by 3 gets us 9x+3y=9. basically multiplying each term by 3. now just do the same thing from the first part, so start with the new 9x+x and continue