SOLUTION: solve the following system bu substitution x=7y+9 x=7/4y what is the solution set? solve by the substitution method. x-y=-1 7x+3y=-67 what is the solution set?

Question 583100: solve the following system bu substitution
x=7y+9
x=7/4y
what is the solution set?

solve by the substitution method.
x-y=-1
7x+3y=-67
what is the solution set?

solve by the elimination method.
2x-5y=36
5x+7y=-27
what is the solution set?

use the elimination method to solve the system of equations.
5x+4y=5
-7x-8y=-19
what is the solution set?
Found 2 solutions by solver91311, JBarnum:
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!

Was there some part of "One question per post" that you are having trouble comprehending?

John

My calculator said it, I believe it, that settles it

Answer by JBarnum(2146) (Show Source): You can put this solution on YOUR website!
Ill do one substitution and one elimination that way you can see the difference you should be able to get the other 2 just fine

Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=2080 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 0.171553875070813, -1.4572681607851. Here's your graph:

y=.1716
y=-1.4573

x=10.2012
x=-1.2011
_______________
2x-5y=36
5x+7y=-27
im going to eliminate the ys
multiply top equation by 7 and bottom by 5

.

add the equations together
.
add like terms
.
divide by 39
.

.
imput x value and solve for y

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