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raebaby420
What is a possible first step in eliminating a variable in the following system of equations? x + 7y = –15 2x + 7y = –9
MY answer choices Multiply the first equation by –1. Multiply the second equation by –1 Multiply the first equation by –2. All of the above
Try doing each one... first, do one of your options, like multiply the first equation by -1. Now add it to the 2nd equation and see if a variable disappears. So for the first case, you have \[(x+7y=-15) *(-1)\] which gives you \[-x-7y=15\] If you add that to the 2nd equation, you'll eliminate the 7y. Try for the other 2.
all of the above :)