Let last year's income be x and this year's income be y.

(y-x)/x=20%

y- 1750-5000 =(x-5000)( 1-5%)

(y-x)/x=20%

Y= 1.2x into the second equation.

1.2x- 1750-5000 =(x-5000)×95%

1.2x-6750=0.95x-4750

0.25x=2000

X=8000，y=9600。 The income this year is 9600 yuan, and the expenditure is 9600-5000- 1750=2250 yuan.

2:

The solution is reciprocal.

That is x =-y.

counter-balance

-y-5y=2p

-3y+7y=p- 14

-y-5y=2p

y=-p/3

Introduce the second equation

-4p/3=p- 14

7p/3= 14

p=6，y=-2，x=2