(x-79)[400+10(99-x)]=5000
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(x-79)[400+10(99-x)]=5000(x-79)(400+990-10x)=5000(x-79)(139-x)=500139x-x²-10981+79x=500-x²+218x=11481x²-218x=-11481(x-109)²-109²=-11481(x-109)²=400x-109=±20x=129,x=89
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(x-79)[400+10(99-x)]=5000
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(x-79)[400+10(99-x)]=5000(x-79)(400+990-10x)=5000(x-79)(139-x)=500139x-x²-10981+79x=500-x²+218x=11481x²-218x=-11481
(x-109)²-109²=-11481(x-109)²=400x-109=±20x=129,x=89
x=129,x=89
(x-79)[400+10(99-x)]=5000(x-79)(400+990-10x)=5000(x-79)(139-x)=500139x-x²-10981+79x=500-x²+218x=11481x²-218x=-11481(x-109)²-109²=-11481(x-109)²=400x-109=±20x=129,x=89