Toán Lớp 8: Phân tích các đa thức sau thành nhân tử a, 36-x^2 b, x^2-y^2 c, x^2-4y^2 d, 9x^2-1 e, 4x^2-9 g, 4x^2-9 i, 25x^2-y^2 k, x^4-1

Question

Toán Lớp 8:  Phân tích các đa thức sau thành nhân tử a, 36-x^2 b, x^2-y^2 c, x^2-4y^2 d, 9x^2-1 e, 4x^2-9 g, 4x^2-9 i, 25x^2-y^2 k, x^4-1

dinhcongson · Answer

a) 36 - x&sup2;   =6&sup2; - x&sup2;   =(6-x)(6+x)   b) x&sup2; - y&sup2;   =(x-y)(x+y)   c)x&sup2; - 4y&sup2;   =x&sup2; - (2y)&sup2;   =(x-2y)(x+2y)   d)9x&sup2; - 1   =(3x)&sup2; - 1&sup2;   =(3x-1)(3x+1)   e)4x&sup2; - 9   =(2x)&sup2; - 3&sup2;   =(2x-3)(2x+3)   g)4x&sup2; - 9   =(2x)&sup2; - 3&sup2;   =(2x-3)(2x+3)   i)25x&sup2; - y&sup2;   =(5x)&sup2; - y&sup2;   =(5x-y)(5x+y)   k)x^4 - 1   =(x&sup2;)&sup2; - 1&sup2;   =(x&sup2; - 1)(x&sup2;+1)   =(x-1)(x+1)(x&sup2;+1)

tongtung · Answer

Gửi bạn:   $a,$ $36-x^2$   $=6^2-x^2$   $=(6-x)(6+x)$   $b,$ $x^2-y^2$   $=(x-y)(x+y)$   $c,$ $x^2-4y^2$   $=x^2-(2y)^2$   $=(x-2y)(x+2y)$   $d,$ $9x^2-1$   $=(3x)^2-1$   $=(3x-1)(3x+1)$   $e,$ $4x^2-9$   $=(2x)^2-3^2$   $=(2x-3)(2x+3)$   $g,$ Tương tự c&acirc;u $e$   $i,$ $25x^2-y^2$   $=(5x)^2-y^2$   $=(5x-y)(5x+y)$   $k,$ $x^4-1$   $=(x^2)^2-1$   $=(x^2-1)(x^2+1)$   $=(x-1)(x+1)(x^2+1)$