Question

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

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

Answer 1

3X+7Y+5=0.,..,..,.,..(1)
4X-3Y-8=0..,,..,.,...,..(2)
From (1) x=(-5-7y)/3..,..,..(3) put into equ (2) for x ; (-20-28y)/3-8=0 ; y=31/28=1.1 put into equ 3 for y
x=(-5-7.7)/3=-4.2
-4.2p +1.1-1=0 ; p=-0.1/-4.2
p=0.024

Answer 2

first times 3 ---> 9x + 21y = -15
2nd times 7 ---> 28x - 21y = 56
add them
37x = 41
x = 41/37

sub into 1st:
3(41/37) + 7y = -5
7y = -5 - 123/37 = -308/37
y = -44/37

then if px + y = 1
p(41/37) - 44/37 = 1
p = (1 + 44/37)(37/41) = <b>81/41</b>

I verified the above answers, they satisfy the original equations.

Answer 3

37-32-2-47-81