Question

Solve the system of equations using the of substitution 8x+4y=15, x+y=3​

Answer 1

Hi there!

`\large\boxed{x = (3)/(4), y = (9)/(4)}}`

8x + 4y = 15

x + y = 3

Use the second equation to solve for a particular variable since it is easier to isolate. We can begin by solving for y:

x + y = 3

Subtract y from both sides:

x = -y + 3

Substitute in this expression for x into the other equation:

8(-y + 3) + 4y = 15

Distribute and simplify:

-8y + 24 + 4y = 15

-4y + 24 = 15

-4y = -9

y = 9/4

Substitute in this value of y to solve for x:

8x + 4(9/4) = 15

8x + 9 = 15

8x = 6

x = 6/8 = 3/4

The values respectively are:

x = 3/4, y = 9/4