Question 1205724: Solve the system by the substitution method. If there is exactly one solution, write as an ordered pair. If not, choose one of the other options.
{(7x,-,7y,=,-28),(6x,+,y,=,-10):}
A. One solution:
B. No solution
C. Infinite number of solutions
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39617)   (Show Source):
Answer by ikleyn(52781)  (Show Source):
You can put this solution on YOUR website! .
Solve the system by the substitution method. If there is exactly one solution,
write as an ordered pair. If not, choose one of the other options.
7x - 7y = -28,
6x + y = -10.
A. One solution:
B. No solution
C. Infinite number of solutions
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From second equation, express y = -10-6x.
Now substitute this expression into first equation. You will get
7x - 7*(-10-6x) = -28
You have now one equation with one unknown x.
Simplify this equation and find x from it
7x + 70 + 42x = -28
7x + 42x = -28 - 70
49x = -98
x =  = -2.
Thus you just found out one unknown x= -2.
To find y, use this expression y = -10-6x = -10 - 6*(-2) = -10 + 12 = 2.
ANSWER. The system has one and only one solution x= -2, y= 2.
To check your solution, substitute these found values into equations
and make sure that in each equation the number in the left side is the same as in the right side.
Solved, with all necessary explanations.
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From my post, learn how to write your problem, when you post it to this forum.
Do not use so many commas: they are unnecessary, so take them out.
Simply write each equation in separate line and do not use commas.
Also, do not use curved brackets: they also are unnecessary.
Happy learning (!)
Come again to this forum soon to learn something new.
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