Solve the following system of equations. Round your answers to the nearest tenth. Your answer will be in the form: (M,N). Find M + N, rounded to the nearest tenth.
5x+2y=21
-2x+6y=-34
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OpenStudy (anonymous):
A) 5x + 2y = 21
B) -2x + 6y = -34
2xA = ?
5xB = ?
OpenStudy (anonymous):
say...
OpenStudy (anonymous):
wait 2xA.... and 5xB?
OpenStudy (anonymous):
yes I meant this:
\[2\times(5x+2y) = 2\times(21)\]
and this:
\[5\times(-2x+6y)= 5\times (-34)\]
OpenStudy (anonymous):
okay let me try it
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OpenStudy (anonymous):
10x+4y=42
-10x+30y=-170
like that?
OpenStudy (anonymous):
yes! :)
and now find this:
A + B = ?
OpenStudy (anonymous):
D: okay
OpenStudy (anonymous):
how am i going to erase the x variable when it is already a negative?!?! DDD:::
OpenStudy (anonymous):
would it be 0x+34y=-128?
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OpenStudy (anonymous):
in this way:
A + B = (10x-10x) + 34y = -128
->
34y = -128
OpenStudy (anonymous):
yes :)
OpenStudy (anonymous):
so find y...
OpenStudy (anonymous):
y=-3.76470588
hartnn (hartnn):
just to give an alternate way:
multiply A) by 3 and subtract the equations..
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OpenStudy (anonymous):
yes,@hartnn said...and you found y,so you can find x .. ;)