Question

Solve the equations by substitution method: A) x+y=3, 2x+5y=12.​

Answer 1

x = 1, y = 2

Explanation:

Original equations:

`x+y=3\\2x+5y=12`

Substitute y and solve for x:

`y=3-x\\2x+5y=12`

`2x+5(3-x)=12`

`2x+15-5x=12`

`-3x=-3`

`x=1`

Plug in x to solve for y:

`1+y=3`

`y=2`

x = 1, y = 2

Note: You can also substitute x and solve for y, then plug in y to solve for x. I did not do that here.

Answer 2

x+y=3

x=3-y equation 1

2x+5y=12

2(3-y)+5y=12

6-2y+5y=12

6+3y=12

3y=12-6

y=6÷3

y=2 equation 2

again ,

putting value of equation 2 in equation 1

x=3-y

x=3-2

x=1