You can put this solution on YOUR website! How do I solve 5x+4y=7 and x-3y=9.
:
We can use the 2nd equation for substitution:
x - 3y = 9
which is:
x = 3y + 9
:
Substitute (3y+9) for x in the 2nd equation. find y:
5x + 4y = 7
:
5(3y+9) + 4y = 7
:
15y + 45 + 4y = 7
:
15y + 4y = 7 - 45
:
19y = -38
y =
y = -2
:
Find x, substitute -2 for y, in equation: x = 3y + 9
x = 3(-2) + 9
x = +3
:
Check solution in the 1st original equation; 5x + 4y = 7
5(3) + 4(-2) =
15 - 8 = +7
:
:
I have to find the graph
:
Arrange equation into the general y= form
5x + 4y = 7
4y = 7 - 5x
y = - x
:
x - 3y = 9
-3y = 9 - x
y = +
y = - 3
:
Plot these two equations;
:
Note the point of intersection is x=3, y=-2, our solution
