how to solve 2x+3y=20; 1x+2y=11.25

Question

I need to know how to solve these types of problems, and what is the answer to this question

2x+3y=20

1x+2y=11.25

Answer 1

2x + 3y = 20

x + 2y = 11.25

multiply the second equation by -2 on both sides

2x + 3y = 20

-2x - 4y = -22.5

add the equations straight down

0x - y = -2.5

divide both sides by -1

0x + y = 2.5

y = 2.5

Put y = 2.5 into one of the original equations.

x + 2y = 11.25

x + 2(2.5) = 11.25

x + 5 = 11.25

x = 6.25

Answer:  x = 6.25, y = 2.5