Question

Solve:
3x + 7y + 5= 0
4x - 3y - 8 = 0

Find p; if:
px + y - 1= 0

Answer 1

I.
3x + 7y + 5 = 0
4x - 3y - 8 = 0

To solve, we can either use substitution or elimination method. For substitution, we choose one equation and represent one variable in terms of the other. Let's choose the first equation, and represent x in terms of y:
3x + 7y + 5 = 0
3x = -7y - 5
x = (-7/3)y - 5/3
then we substitute this to the 2nd equation:
4x - 3y - 8 = 0
4[(-7/3)y - 5/3] - 3y - 8 = 0
(-28/3 y - 20/3 - 3y - 8 = 0)*3
-28y - 20 - 9y - 24 = 0
-37y = 44
y = -44/37
substituting this back to either equations and solving for x,
x = 41/37

II.
px + y - 1= 0
px = 1 - y
p = (1-y)/x

hope this helps~ :)