Question

Use substitution method to solve x-2y-5=0, 3x-5y=8

Answer 1

To do substitution method, we choose an equation and express one of the variables in terms of the other, and finally substitute this to the other equation.
In this case, let's choose the first given equation and express x in terms of y:
x - 2y - 5 = 0
x = 2y + 5
then we substitute this to the second equation:
3x - 5y = 8
3(2y + 5) - 5y = 8
6y + 15 - 5y = 8
y = 8 - 15
y = -7
finally, we substitute this value of x to get y:
x = 2(-7) + 5
x = -14 + 5
x = -9

hope this helps~ :)