Raul was working on some Solving Systems of Equations problems. When he was checking his solutions, he found two problems with incorrect solutions. Find the errors Raul made on the following two problems. Explain what he did wrong for both of these problems and give the correct answers.
Problem 1:
Solve by substitution
4x + 7y = 1
y = -2x-7
4x + 7(-2x-7) = 1
4x-14x-7 = 1
-10x-7 = 1
-10x = 8
x = 8-10
x = -45
y = -2(-45) -7
y = 85-7
y = 85-355
y = -275
(-45,-275)
Problem 2:
Solve by elimination
5x-2y = -2
4x-3y = 4
-15x + 6y = 6 (multiplied first eq by -3)
+ 8x-6y = 4 (multiplied second eq by 2)
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-7x = 10
x = -107
5(-107)-2y = -2
-507-2y = -2
-2y = -147+507
-2y = 367
y = -187
(-107, -187)