Question

If 4x+3y=23,3x-3y=-9 then the value of x+y

Answer 1

Answer:

x=2

y=5

x+y=7

Given:

Two Equation:

1) 4x+3y=23 ...............(i)

2) 3x-3y=-9 ...............(ii)

To Calculate:

Value of x+y

Explanation:

Adding equation (i) and (ii), we get,

4x+3x+3y-3y=23-9

Cancelling 3y from LHS and adding 4x and 3x in LHS

7x=14

Dividing both sides by 7, we get,

x=2

Substituting the value of x in (i), we get,

8+3y=23

Subtracting 8 from both sides, we get,

3y=15

Dividing both sides by 3, we get,

y=5

Value of x+y

x+y=2+5

x+y=7

Some Points to Note:

1) In some questions of Linear Equation, the question is not simple like this one.

In such types of questions, we may have to either multiply or divide or do other necessary calculations to solve the question.

2) If the linear equation is in fraction, then we cross multiply the LHS and RHS and then solve the equation by performing necessary calculations.

3) If the denominator of the linear equation is in root, then we have to rationalise the denominator by multiplying the fraction by rationalising factor (denominator only) so that the root is eliminated from the denominator.