Question

Q1.Find the value of x and y
3x+ 7y=27
5x+2y=60​

Answer 1

Explanation:

We have given two Equations :3x+7y=27 & 5x+2y=60 .We can solve it in various ways here ,we will solve it through substitution method and elimination method.

➙3x+7y=27------(×5)

➙5x+2y= 60-----(×3)

New Equation obtained

➙15x+35y=135

➙15x+6y=180

➙(-)(-)\:(-)(−)(−)(−)

____________

29y= -45

y= -45/29

Put y's value into this equation

➙5x+2y= 60

➙5x+2(-45/29)=60

➙5x-90/29= 60

➙5x=60+90/29

➙5x= 1740+90/29

➙5x= 1830/29

➙x= 1830/29×1/5

➙x= 366/29

x= 366/29

Check:

3x+7y= 27

Taking LHS

➙3(366/29)+7(-45/29)

➙1098/29-315/29

➙783/29

=27

Since,LHS = RHS(Verified)

Alternative Method:

By substitution method:

➙3x+7y= 27-------(1)

➙5x+2y=60-------(2)

From equation 1

x= (27-7y)÷3----------(3)

Put Equation 3 into Equation 2

➙5(27-7y/3)+2y= 60

➙135-35y/3+2y= 60

➙135-35y+6y/3=60

➙135-29y= 180

➙-29y= 180-135

➙-29y= 45

➙y= -45/29

put y's value into equation 3

➙x=27-7y/3

➙x= 27-7(-45/29)/3

➙x= (27+315/29)÷3

➙x= (783+315)/29÷3

➙x= 1098/29×1/3

➙x= 366/29