Question 1073788: Given that
5a - 7b + 3c = 19,
2a - 4b + c = 77,
determine the value of a+b+c. Thank you. Found 2 solutions by Edwin McCravy, ikleyn:Answer by Edwin McCravy(20059) (Show Source):
Let the answer be a+b+c = x
Then we have this system:
Eliminate the c's from the first and third equations by
multiplying the first equation by -1 and adding it
to the third equation:
We get
Eliminate the c's from the first and second equations
by multiplying the first equation by -3 and adding it
to the second equation:
We get
Next we have these two equations with c eliminated:
Eliminate the left side by multiplying the first
equation through by -2:
Adding the equations we get:
or
Answer a+b+c = x = -135
Edwin
You can put this solution on YOUR website! .
Given that
5a - 7b + 3c = 19,
2a - 4b + c = 77,
determine the value of a+b+c. Thank you.
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5a - 7b + 3c = 19, (1)
2a - 4b + c = 77. (2)
Multiply equation (2) by 2 (both sides). Write the updated system:
5a - 7b + 3c = 19, (1)
4a - 8b + 2c = 154. (2')
Subtract equation (2') from equation (1) (both sides). You will get
a + B + c = 154-19 = -135.
Answer. a + b + c = -135.
