平方差........20點

平方差

9/1(3p+9q)(9q-3p) <-- 對唔往，真的看不懂




(x-1)2次+(x-a)(x+2)全等2x 的2次-3x+b

求a和b的值.....

你的意思是： (x - 1)^2 + (x - a) (x + 2) = 2 x^2 - 3x + b???

L.H.S. = (x - 1)^2 + (x - a) (x + 2)
= x^2 - 2x + 1 + x^2 - ax + 2x - 2a
= 2 x^2 - ax + (1 - 2a)


comparing coeff.
- a = - 3 and 1 - 2a = b

so, a = 3

b = 1 - 2 x 3 = - 5

What is your a???
Because if you don't tell me,I can't help you><"
如不選我，請及早告知，好讓採用率不至於下降，謝謝！

你都無答案,點求值?
設答案為y
a+b=y/2/2/+3x+B(x+2)-(x-2)/2-(x+a)