Question

solve for x and y:7*x+5*y=74 and 7*(x+1)-5*(y+1)=218

Answer 1

7x+5y=74.....(1)
7(x+1)-5(y+1)=218
7x+7-5y-5=218
7x-5y+2=218
7x-5y=218-2
7x-5y=216....(2)
Adding eq 1and 2
7x+5y=74
7x-5y=216
14x=290
x=290/14
x=20.71
putting the value of x in eq 1
7x+5y=74
7×20.71+5y=74
144.97 + 5y=74
5y=74-144.97
5y=70.97
y=70.97/5
y=14.19

Answer 2

Answer:

7  

x

+5  

y

=74 ____ (1)

7  

x+1

−5  

y+1

=218

7  

x

.7−5  

y

.5=218  __ (2)

Leta=7  

x

;b=5  

y

 

a +b = 74  

a = 74 - b  ___ (3)

7a -5b = 218  ___ (4)

Put (a) in (4)  

7 (74 - b) -5b = 218

518 - 7b -5b = 218

518-218 = 12b

b = 300/12

b = 25

Put 'b' in   (3)

a = 74 - 25 = 49

but   a=7  

x

 

7  

x

=49=7  

2

 

∴x=2

b = 25

5  

y

=5  

2

 

∴y=2