Toán Lớp 8: a)-10x^2-17x+6 b)-10x^2+28x+6 c)10x^2-28x-6 d)10x^2-7x-12 đ)-10x^2+7x+12 e)10x^2-14x-12

Question

Toán Lớp 8:  a)-10x^2-17x+6 b)-10x^2+28x+6 c)10x^2-28x-6 d)10x^2-7x-12 đ)-10x^2+7x+12 e)10x^2-14x-12

doanthulan · Answer

Giải đáp:   a)(x+2)(3-10x)   b)-2(x-3)(5x+1)   c)2(x-3)(5x+1)   d)(2x-3)(5x+4)   đ)(3-2x)(5x+4)   e)2(x-2)(5x+3)   Lời giải và giải thích chi tiết:   a)-10x&sup2;-17x+6   =-10x&sup2;-20x+3x+6   =(-10x&sup2;-20x)+(3x+6)   =-10x(x+2)+3(x+2)   =(x+2)(3-10x)   b)-10x&sup2;+28x+6   =-2(5x&sup2;-14x-3)   =-2(5x&sup2;-15x+x-3)   =-2[(5x&sup2;-15x)+(x-3)]   =-2[5x(x-3)+(x-3)]   =-2(x-3)(5x+1)   c)10x&sup2;-28x-6   =2(5x&sup2;-14x-3)   =2(5x&sup2;-15x+x-3)   =2[(5x&sup2;-15x)+(x-3)]   =2[5x(x-3)+(x-3)]   =2(x-3)(5x+1)   d)10x&sup2;-7x-12   =10x&sup2;-15x+8x-12   =(10x&sup2;-15x)+(8x-12)   =5x(2x-3)+4(2x-3)   =(2x-3)(5x+4)   đ)-10x&sup2;+7x+12   =-10x&sup2;+15x-8x+12   =(-10x&sup2;+15x)-(8x-12)   =-5x(2x-3)-4(2x-3)   =(2x-3)(-5x-4)   =(3-2x)(5x+4)   e)10x&sup2;-14x-12   =2(5x&sup2;-7x-6)   =2(5x&sup2;-10x+3x-6)   =2[(5x&sup2;-10x)+(3x-6)]   =2[5x(x-2)+3(x-2)]   =2(x-2)(5x+3)

maitrucloan · Answer

Lời giải:     a)   -10x^(2)-17x+6   =-10x^(2)-20x+3x+6   =-10x(x+2)+3(x+2)   =(x+2)(-10x+3)   b)   -10x^(2)+28x+6   =-10x^(2)+30x-2x+6   =-10x(x-3)-2(x-3)   =(x-3)(-10x-2)   =-2(x-3)(5x+1)   c)   10x^(2)-28x-6   =10x^(2)-30x+2x-6   =10x(x-3)+2(x-3)   =(x-3)(10x+2)   =2(x-3)(5x+1)   d)   10x^(2)-7x-12   =10x^(2)-15x+8x-12   =5x(2x-3)+4(2x-3)   =(2x-3)(5x+4)   đ)   -10x^(2)+7x+12   =-10x^(2)+15x-8x+12   =-5x(2x-3)-4(2x-3)   =(2x-3)(-5x-4)   e)   10x^(2)-14x-12   =2(5x^(2)-7x-6)   =2(5x^(2)-10x+3x-6)   =2[5x(x-2)+3(x-2)]   =2(x-2)(5x+3)