Toán Lớp 8: ìm x biết: ( 2x + 3). ( x – 4) + ( x -5 ) . ( x – 2) = ( 3x – 5 ) . ( x – 4 )
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Toán Lớp 8: ìm x biết: ( 2x + 3). ( x – 4) + ( x -5 ) . ( x – 2) = ( 3x – 5 ) . ( x – 4 )
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=>2x.(x-4)+3.(x-4)+x(x-2)-5.(x-2)=3x.(x-4)-5.(x-4)
=>2x^2-8x+3x-12+x^2-2x-5x+10=3x^2-12x-5x+20
=>2x^2-5x-12+x^2-7x+10=3x^2-17x+20
=>2x^2-5x-12+x^2-7x+10-3x^2+17x-20=0
=>(2x^2+x^2-3x^2)+(-5x-7x+17x)+(-12+10-20)=0
=>5x-22=0
=>5x=0+22
=>5x=22
=>x=22/5
Vậy x=22/5