SOLUTION: Solve the systems of equations by substitution:
3x+y= -8
4x+3y=7
I have been working with different types of equations all night on homework and I'm not sure if I just don't un
Algebra.Com
Question 997949: Solve the systems of equations by substitution:
3x+y= -8
4x+3y=7
I have been working with different types of equations all night on homework and I'm not sure if I just don't understand it or if I'm doing something small wrong I just can't seem to get the correct answer.
Found 2 solutions by MathLover1, addingup:
Answer by MathLover1(20849) (Show Source): You can put this solution on YOUR website!
Solve the systems of equations by substitution:
....eq.1
....eq.2
-------------------------
start with ....eq.1, solve for
...eq.1a...now, substitute it in eq.2
....eq.2....solve for
....now, go back to ...eq.1a,substitute for and find
Answer by addingup(3677) (Show Source): You can put this solution on YOUR website!
3x+y= -8
4x+3y= 7
We can begin with either one of the equations, but since we have a "y" all by itself in the first equation, let's start with the first equation:
3x+y= -8
y= -8-3x
Now we plug this value for y into the second equation (Warning: If we substitute into the same equation we would get a true, but useless, statement. Always substitute into the other equation)
4x+3(-8-3x)= 7 Now we can solve for x:
4x+-24-9x= 7
= 4x-24-9x= 7 Add 24 on both sides and add x on left:
-5x= 31
x= 31/-5= -6 1/5 And y?:
y= -8-3(-6 1/5)
y= -8+18 3/5
y= 26 3/5
J
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