中一既數學有問題..要有列式同答案(10).

(1)
2a + 3a - a
= 5a + a
= 6a

(2)
4b-2b+3b
= 2b + 3b
= 5b

(3)
2*t*3t
= (2*3)x(t*t)
= 6t²

(4)
4*r/8r
= (4/8)*(r/r)
= 1/2

(5)
c*4c - c²
= 4*c*c - c²
= 4c² - c²
= 3c²

(6)
(x + x²)/2x = x(1 + x)/2x
= (1 + x)/2

但 x + (x²/2x)
= x + (x/2)
= (2x + x)/2
= 3x/2

2011-01-02 20:19:46 補充：
第(1)題忙中有錯，應為：
2a + 3a - a
= 5a - a
= 4a ...... (答案)