(A+B)+(A-B)x=3x+5

(A+B)+(A-B)x=3x+5
A + B = 5 ___(1)
A – B = 3 ___(2)
(1)式加(2)式
2A = 8
A = 4
(1)式減(2)式
2B = 2
B = 1

(A + B) = 5 and (A - B) = 3
i.e. A - B = 3
A = 3 + B
substitute into A + B = 5
3 + B + B = 5
2B = 2
B = 1
then substitute B = 1 into A = 3 + B
= 3 + 1
= 4

thus, A = 4 and B =1

A-B=3 A+B=5

A=4 B=1

let a + b = 5 ( 1 )
let a - b = 3 ( 2 )

( 1 ) + ( 2 )
2a = 8
a = 4#

Sub a = 4 to ( 2 )
4 - b = 3
b = 1#

(A+B)+(A-B)x=3x+5

Therefore,
A+B=5 and A-B=3

Therefore, A =4, B =1