MATH F.1

Step 1. Eliminate the brackets by using the distributive law.
4(2x -3) -8 = 7 - 2(3x -4)
4(2x) -(3)(4) -8 = 7 - [2(3x) -4(2)]
8x - 12 - 8 = 7 - (6x - 8)
8x -12 - 8 = 7 -6x +8
Step 2. Group like terms.
8x - 20 = 15 - 6x
Step 3.
Put all unknown terms on one side of the equation and all other terms on the other side of the equation.
8x + 6x = 15 + 20
14x = 35
Therefore, x = 35/14 = 5/2.

你們先不要急著相乘出來 有時可以轉一轉計算方式

4(2x-3) - 8 = 7-2(3x-4)
4(2x-3) + 2(3x-4) = 7+8
2[2(2x-3)] + 2(3x-4) = 15
2(4x-6+3x-4) = 15
7x-10 = 15/2
7x = 15/2 + 10
x = [(15+20)/2] /7
x = 35/14 = 2.5

4(2x-3)-8=7-2(3x-4)

(4)(2x)-(4)(3)-8=7-(2)(3x)+(2)(4)

8x-12-8=7-6x+8

8x+6x=12+8+7+8

14x=35

x=2.5





2008-06-06 18:53:19 補充：
代入:

4(2x-3)-8=7-2(3x-4)

4(5-3)-8=7-2(7.5-4)

8-8=7-15+8

0=0

所以x=2.5