Algebra Problems With Substitution
Can someone please help with these algebra problems?
Solve the system by substitution.
5x + 2y = –15
y = 2x – 12
Solve the system by addition.
x + y = 4 x – y = 4
Thanks
Substitution means to put (2x – 12) into the first equation where the “y” was.
5x + 2(2x – 12) = -15 Then distribute the 2
5x + 4x – 24 = -15 Add the similar terms
9x – 24 = -15 Add 24 to both sides
9x = 9 Divide by 9
x = 1
Solve for y
y = 2(1) – 12
y = 2 – 12 = -10
Solving by addition works better if you stack the equations one on top of the other.
x + y = 4
x – y = 4 Adding down the columns gives
2x = 8
x = 4 Put that back in and y = 0
WORD PROBLEM 1: Substitution, Elimination Method: Linear Algebra: Systems of Equations
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