中一數學 (5)

(3x+5)/4 - (2x+2)/3 = 1
(3x+5)3 - (2x+2)4 = 1(12)
9x+15-8x-8=12
x=5

(3x 5)/4 - (2x 2)/3 = 1

首先要通分母, 所以要乘12

(3x 5)/4*12 - (2x 2)/3 *12 = 1*12
3(3x 5) -4 (2x 2) = 12
9x 15 -8x-8 = 12
9x -8x 15-8 = 12
x 7 = 12
x = 12-7
x = 5

(3x+5)/4 - (2x+2)/3 = 1
(9x+15)/12-(8x-8)12 = 1
( 9x-8x+15-8)/12 =1
(x+7)/12 =1
x+7 = 1x12
x+7 =12
x =12-7
x = 5

x=5 ar!!

(3x+5)/4 - (2x+2)/3 = 1
(3x+5)/4乘12- (2x+2)/3乘12=1 (因為要通分母)
9x+15-8x-8=1
x=9-15
x=-6
再代x=-6入去9x+15-8x-8=1
9乘(-6)+15-8乘(-6)-8=1
所以x=6是正確的

(3x+5)/4 - (2x+2)/3 = 1
(3x+5) - (2x+2)/3*4 = 1*4
(3x+5) - (8x+4)/3 = 4
(3x+5)*3 - (8x+4) = 4*3
(9x+15) - (8x+4)=12
9x+15-8x-4=12
9x-8x=12-15+4
x=1