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