Question 208751
7y -63,,,,,,+xy-9x
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7(y-9),,,,,+x(y-9)
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(7+x)*( y-9),,,,,answer
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often  hard to  visualize the  last  step,,,,starting  at  ab+cb = b(a+b),,,
let  a=7,,,b= (y-9),,,c=x,,,,,,,7(y-9) + x(y-9) = (y-9)(7+x)
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