Toán Lớp 8: Rút gọn phân thức :
(2x-4)^2-9/2x^2-x
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Toán Lớp 8: Rút gọn phân thức :
(2x-4)^2-9/2x^2-x
Comments ( 2 )
= {(2x-4)^2 -3^2}/{x(2x-1)}
= {(2x-4-3)(2x-4+3)}/{x(2x-1)}
= {(2x-7)(2x-1)}/{x(2x-1)}
= {2x-7}/x
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Áp dụng HĐT số 3: $A^2 – B^2 =(A-B)(A+B)$