Answer:
x = 1
y= -2
Explanation:
to solve this system of equation , simultaneously using the substitution method
we say let
7 x + y = 5 ............................................. equation 1
2x - y = 4 ................................................... equation 2
from equation 2
2x - y = 4 ................................................... equation 2
2x - 4 = y
y = 2x -4.......................................................... equation 3
put the value of the y = 2x -4 into equation 1
7 x + y = 5 ............................................. equation 1
7x + 2x - 4 = 5
9x-4 = 5
9x = 5 + 4
9x = 9
divide both sides by the coefficient of x which is 9
9x/9 = 9/9
x = 1
substitute the value of x = 1 into equation 3
y = 2x -4.......................................................... equation 3
y = 2(1) -4
y = 2 - 4
y = -2
to check if you are correct put the value of x and y into any of the equations and you will see that the left hand side will be equal to the right hand side.
2x - y = 4 ................................................... equation 2
2(1) -(-2) = 4
2 + 2 = 4
4=4................................... proved