Question

does anyone know how to solve 2x+3y=7 and 4x-5y=25 using substitution to solve the system of equations. PLEASE HELP ONLY IF YK IT

Answer 1

x = 5, y = - 1

Explanation:

2x + 3y = 7

4x - 5y = 25

In the second equation, solve for y in terms of x:

4x - 5y = 25

- 5y = 25 - 4x

- y = 5 - 4x/5

y = - 5 + 4x/5 Now substitute this for y in equation 2x + 3y = 7

2x + 3(-5 + 4x/5) = 7

2x - 15 + 12x/5 = 7

10x/5 - 15 + 12x/5 = 7

22x/5 = 7 + 15

22x/5 = 22 Now multiply both sides by 5/22 to isolate :

x = 5

Now substitute this value (x = 5) into 4x - 5y = 25 to solve for y:

4(5) - 5y = 25

20 - 5y = 25

- 5y = 5

y = - 1

You can check that these are correct by substituting x = 5 and y = -1 into the above equations to make sure they check out.

Answer 2

x = 5, y = -1

Explanation:

2x+3y=7

4x-5y=25

Keep the second equation the same, but change the first equation so you have something to substitute into.

3y= -2x+7

y= -2/3x + 7/3

substitute into second equ.

4x + 10/3x - 35/3 = 25

put the variables on one side, and the numbers on the other.

22/3x = 110/3

divide by 3

22x = 110

x = 5

Substitute x = 5 into the first equation,

10 + 3y = 7

move numbers to one side, and variables to the other.

3y = -3

y = -1