SOLUTION: I still need some help graphing 4x + 5y = -2 4y - x = 11 THANKS SO MUCH.

Algebra ->  Linear-equations -> SOLUTION: I still need some help graphing 4x + 5y = -2 4y - x = 11 THANKS SO MUCH.      Log On


   

Question 186832: I still need some help graphing
4x + 5y = -2
4y - x = 11
THANKS SO MUCH.
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!

4x+%2B+5y+=+-2+---->EQN 1
4y+-+x+=+11-----> EQN 2
Based on Slope-Intercept Form:system%28y=mx%2Bb%29
In EQN 1: 5y=-4x-2--->cross%285%29y%2Fcross%285%29=%28-4x-2%29%2F5
y=%28-4%2F5%29x-2%2F5, EQN 1.1
Let fy=0
0=%28-4%2F5%29x-2%2F5---->%284%2F5%29x=-2%2F5
cross%284%2F5%29x%2Fcross%284%2F5%29=%28-2%2F5%29%2F%284%2F5%29=%28-2%2F5%29%285%2F4%29
x=-2%2F4=-1%2F2, X-Intercept
Let fx=0:
y=%28-4%2F5%29%280%29-2%2F5=-2%2F5, Y-Intercept
.
In EQN 2:
4y=x%2B11--->cross%284%29y%2Fcross%284%29=%28x%2B11%29%2F4
y=%281%2F4%29x%2B11%2F4, EQN 2.2
Let fy=0:----> 0=%281%2F4%29x%2B11%2F4
%281%2F4%29x=-11%2F4---->cross%281%2F4%29x%2Fcross%281%2F4%29=%28-11%2F4%29%2F%281%2F4%29
x=-11, X-Intercept
Let fx=0:----> y=%281%2F4%29%280%29%2B11%2F4=11%2F4, Y-Intercept
.
In EQN 2: By Substitution,
4y-11=x----->EQN 3, subst. in EQN 1
4%284y-11%29%2B5y=-2
16y-44%2B5y=-2
21y=-2%2B44=42---->cross%2821%29y%2Fcross%2821%29=cross%2842%292%2Fcross%2821%29
highlight%28y=2%29, Subst. in EQN 3:
x=4%2A2-11=8-11
highlight%28x=-3%29
POINT OF INTERSECTION (-3,2)
We'll see the graph:
--->RED, EQN 1; GREEN, EQN 2
Thank you,
Jojo