Question

Solve each system of equations by substitution X + 3y = 6 -x + y = -7

Answer 1

Answer:

$x = 6.75$

$y = -0.25$

Step-by-step explanation:

Given :

$x + 3y = 6$ ..................... equation 1

$-x + y = -7$ ................... equation 2

solving the system of equation by substitution method , from equation 1 , make x the subject of the formula , that is

$x = 6 - 3y$ ........................... equation 3

substitute equation 3 into equation 2 , that is

$- ( 6 - 3y) + y = -7$

$-6 + 3y + y = - 7$

$-6 + 4y = -7$

$4y = -7 + 6$

$4y = -1$

$y = \frac{-1}{4}$ $= -0.25$

substitute  $y = \frac{-1}{4}$ into equation 3 to find the value of x , that is

$x = 6 - 3 (\frac{-1}{4})$

$x = 6 + \frac{3}{4}$

$x = \frac{27}{4}$

$x = 6. 75$

Therefore :

$x = 6. 75$

$y = - 0.25$