Question

Solve the following using substitutionY = 2X - 34X -3Y = 31

Answer 1

In order to solve the given substitution we just have to replace 2X - 3 for y into 4X - 3Y = 31, like this:

4X - 3Y = 31

4x - 3(2x - 3) = 31

4x - 6x + 9 = 31

-2x + 9 = 31

-2x + 9 - 9 = 31 - 9

-2x = 22

-2x/-2 = 22/-2

x = -11

Then, x equals -11. By replacing -11 for x into Y = 2X - 3, we get:

Y = 2X - 3

Y = 2(-11) - 3

Y = -22 - 3

y = -25

Then, the solution is (-11, -25) x equals -11 and Y equals -25