3道简单的初3数学题目求高人解答。高分悬赏

显示全部楼层 · 2011-9-5 22:09:38

注：x^2 表示x的平方。照片72: 因式分解 x^2 +10x-24 = (x-2)(x+12),
x^2 -14x+24 = (x-2)(x-12)
(x^2-2x)^2 - 11(x^2-2x) + 24 =(x^2-2x-3)(x^2-2x-8)= (x-3)(x+1)(x+2)(x-4)照片73: 4xy+1 -4x^2 -y^2= 1- (2x-y)^2 = (1+2x-y)(1-2x+y)照片74: 由韦达定理可得x1 + x2= 7/4, x1*x2=-3/4, 则(1). (x1-3)(x2-3)=x1*x2 -3(x1+x2)+9 =...

千问 · 2011-9-5 22:09:38

第一题，根据韦达定理，X1+X2=-A/B.X1*X2=C/A...

千问 · 2011-9-5 22:09:38

题目...

千问 · 2011-9-5 22:09:38

x^2-14x-24=(x+12)(x-2)x^2-14x+24=(x+12)(x+2)...

千问 · 2011-9-5 22:09:38

enc570...