Question

Solve the following pair of linear (simultaneous) equations using method of subsition : 8x+5y=9 and 3x+2y=6

Answer 1

Answer:

8x+5y=9 --------(1)

3x+2y=6 -------(2)

multiplying eq 1 by 3

and 2 by 8

24x+15y=27 ------(3)

24x+16y=48 ------(4)

(24x-24x)+(16y-15y)=48-27

y=21

substitute the value of y in eq (1)

8x+5(21)=9

8x+105=9

8x=9-105

8x=-96

x=-12

Hence solution of the equation

x=-12 ,. y=21

subtract equation (3)&(4)

Answer 2

Answer:

8X+5y=9

3x+2y=6

3(8X+5y)=27

-8(3x+2y)=-48

24x+15y=27

-24x-16y=-48

-y=-21

y=21

now this value put in ist eq

8X+5y=9

8X+5(21)=9

8x+105=9

8x=9-105

8x=96

X=12

so the required solution is {21, 12}