$\left\{\begin{array}{ccc}x=-2y+300&(1)\\3y=800-4x&(2)\end{array}\right\\\\\text{Substitute (1) to (2):}\\\\3y=800-4(-2y+300)\qquad\text{use the distributive property:}\ a(b+c)=ab+ac\\\\3y=800+(-4)(-2y)+(-4)(300)\\\\3y=800+8y-1200\\\\3y=8y-400\qquad\text{subtract}\ 8y\ \text{from both sides}\\\\-5y=-400\qquad\text{divide both sides by (-5)}\\\\y=80\\\\\text{Put it to (1):}\\\\x=-2(80)+300\\\\x=-160+300\\\\x=140$

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3 years ago

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24=3x-16-8x thank you, sorry not to good at math

antiseptic1488 [7]

First, simplify the equation 3X-8X is -5X. So 24=16+-5X. Then subtract 16 from both sides. So you get 8=-5X. Then divide by -5.
So X= -8/5

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3 years ago

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