Toán Lớp 8: a)x ²-9 b)4x ²-25 c)$x^{6}$ -$y^{6}$ d)9x ²+6xy+y ² e)6x-9-x ²

Question

Toán Lớp 8:  a)x ²-9 b)4x ²-25 c)$x^{6}$ -$y^{6}$  d)9x ²+6xy+y ² e)6x-9-x ²

lanthuhoa · Answer

$#Cat Đ&aacute;ng Y&ecirc;u$    Giải đáp:    a) (x-3)(x+3)   b) (2x-5)(2x+5)   c) (x-y)(x&sup2;+xy+y&sup2;)(x+y)(x&sup2;-xy+y&sup2;)   d) (3x+y)&sup2;   e) -(x-3)&sup2;    Lời giải và giải thích chi tiết:    a)x&sup2;-9   =(x-3)(x+3)   b)4x&sup2;-25   =(2x-5)(2x+5)   c)$x^{6}$ -$y^{6}$    =(x-y)(x&sup2;+xy+y&sup2;)(x+y)(x&sup2;-xy+y&sup2;)   d)9x &sup2;+6xy+y &sup2;   =(3x+y)&sup2;   e)6x-9-x &sup2;   =-(x-3)&sup2;

phuongthaongoc · Answer

a) x^2 - 9     = x^2- 3^2     =(x-3)(x+3)     b)4x^2   - 25      = (2x)^2   - 5^2     =(2x-5)(2x+5)     c)x^6- y^6      = (x^3)^2- (y^3)^2     =(x^3-y^3)(x^3+y^3)     =(x-y)(x^2-xy+y^2)(x^2+xy+y^2)(x+y)     d)    9x^2+6xy+y^2         =(3x)^2+2&times;3xy+y^2         =(3x+y)2     9x^2+6xy+y^2       =(3x)^2+2&times;3xy+y^2       =(3x+y)^2        e)6x&minus;9&minus;x^2         =&minus;(x^2&minus;2&times;3x+32)         =&minus;(x&minus;3)2     6x&minus;9&minus;x^2       =&minus;(x^2&minus;2&times;3x+32)       =&minus;(x&minus;3^)2       Ch&uacute;c bạn học tốt!!