Question 87497This question is from textbook Intermediate Algebra
: Can you please help me with these two problems I would appreciate it.
Solve each system by substitution, if possible. If a system is inconsistent or if the equations are dependent, so indicate.
2x-y=-21
4x+5y=7
and
Solve the system of equations using the addition (elimination) method.
-7x+y=8
2x-y=2
Thank you in advance I really appreciate it.
This question is from textbook Intermediate Algebra
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Solve each system by substitution, if possible. If a system is inconsistent or if the equations are dependent, so indicate.
2x-y=-21
4x+5y=7
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Multiply the 1st equation by 2 to get:
4x-2y = -42
Subtract from 4x+5y=7 to get:
7y = 49
y = 7
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Substitue to solve for x, as follows:
2x-7 = -21
2x = -14
x=-7
-----------
Solution: x=-7; y=7
==========================
Solve the system of equations using the addition (elimination) method.
-7x+y=8
2x-y=2
----------
Add the two equations to eliminate the y terms:
-5x = 10
x = -2
------------
Substitute and solve for y, as follows:
-7*-2+y=8
y=-6
-----------
Check in the other equation:
-7*-2+-6 = 8
8=8
=================
Cheers,
Stan H.
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