- Thread starter SILVER
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J

Does 2x + (-10x) = -12x?SILVER said:here is a problem i don't get:

2x+3y=7

-10x-3y=25

its a problem with two unknowns and the answer is x=-4, y=5. I started by adding the two together and got -12x=32 but when i divided that i got -0.37 and the answer ix=-4.HELP!

I do wonder as well how you divided 32 by -12 and got -0.37.

Need to be more careful

C'mon Silver...SILVER said:2x+(-10x)=-32 does'nt it? when i divided 32 by -12 i got -2.66. How do i get -4?

2x + (-10x) = 32 : NOT -32

-8x = 32

Why would you divide by -12? 2x + (-10x) is not -12x (it isn't 12x, either). It looks like you may need to review addition of signed numbers. Here's a website you can start with (there are many others available online):SILVER said:2x+(-10x)=-32 does'nt it? when i divided 32 by -12 i got -2.66. How do i get -4?

http://www.purplemath.com/modules/negative2.htm