Question

Solve by elimination method
$x + y = 25$
$3x - 4y = 12$
​

Answer 1

Given :-

x + y = 25 , 3x - 4y = 12

To Find :-

The value of "x" and "y" by Elimination Method .

Used Concepts :-

Elimination method .

• If two equations are given to us , whose one variable's Coefficient is same . Then , add or subtract to cancel the variables having same coefficients .
• If the coefficients are not equal then multiply or divide by a number on both sides . Such that the coefficient became same and then cancelled .

Solution :-

Given equation x + y = 25 , 3x - 4y = 12

Let , 3x - 4y = 12 ------ ( i )

x + y = 25 ------ ( ii )

Multiplying by 4 on both sides of ( ii ) we get ,

4x + 4y = 100 ------- ( iii )

Adding ( i ) and ( iii ) ,

3x - 4y = 12

+ 4x + 4y = 100

___________

7x = 112

___________

7x = 112

=> x = 112 / 7

=> x = 16

Therefore , By ( i ) ,

x + y = 25

=> 16 + y = 25

=> y = 25 - 16

=> y = 9

Henceforth , the required value of "x" and "y" are "16" and "9" respectively .