Question

Use the Substitution Method to solve the following system of equations.
x - 4y = 1
2x - 9y = 3

Answer 1

x=1+4y..equ (3)
substitute d value of x in equation 2 which is
2(1+4y)-9y=3
2+8y-9y=3
2-y=3
-y=3-2
-y=1
y=-1.
then substitute the current value of y in equation 1
x-4y=1
x-4(-1)=1
x+4=1
x=1-4
x=-3
so x=-3,y=-1

Answer 2

1st. You have to choose one of the two equations (I'll choose the first one) and express x in terms of y:
x - 4y = 1
x = 1 + 4y

2nd. Substitute x in the second equation:
2x - 9y = 3
2 * (1 + 4y) - 9y = 3
2 + 2*4y - 9y = 3
2 + 8y - 9y = 3
2 - y = 3
2 - 3 = y
y = -1

3rd. You know y, you can find x:
x = 1 + 4y
x = 1 + 4 * (-1)
x = 1 - 4
x = -3