how do you solve:
7x+4y=-4
5x+8y=28 in elmination
Multiply the top equation by 2.
Then subtract the bottom equation from the top.
well first for the 1st equation move everything to one side except y.
You should have y=-1+7/4
now plug that y=1+7/4 into the second equation
8x+8(-1+7/4)=28
8x+6=28
8x=22
x=2.75 or 2 3/4
ok you just found what x is. now plug the value of x back into the first equation
7(2.75)+4y = -4
4y = -23.25
y= -5.8125
I might have done my math wrong, but the process should be right.
baylee, ignore Don. He did not do it by elimination as specified.
Don, stop it.
oh haha sorry. just trying to help.
To solve the system of equations using the elimination method, we need to eliminate one variable (x or y) by adding or subtracting the two equations. Here's how you can do it:
1. Multiply one or both equations by constants to adjust the coefficients of one of the variables so that they cancel out when the equations are added or subtracted.
Looking at the given equations:
Equation 1: 7x + 4y = -4
Equation 2: 5x + 8y = 28
To eliminate the x term, we need to get the coefficients of x to be the same in both equations. Multiply Equation 1 by 5 and Equation 2 by 7:
New Equation 1: 35x + 20y = -20
New Equation 2: 35x + 56y = 196
2. Now, subtract the equations to eliminate the x term:
(New Equation 2) - (New Equation 1):
(35x + 56y) - (35x + 20y) = 196 - (-20)
35x - 35x + 56y - 20y = 196 + 20
36y = 216
3. Solve for y by dividing both sides of the equation by 36:
36y / 36 = 216 / 36
y = 6
4. Substitute the value of y into either of the original equations to find the value of x. Let's use Equation 1 for this example:
7x + 4y = -4
7x + 4(6) = -4
7x + 24 = -4
7x = -4 - 24
7x = -28
x = -28 / 7
x = -4
Therefore, the solution to the system of equations is x = -4 and y = 6.