# Algebraic Methods of Solving a Pair of Linear Equations - Cross - Multiplication Method

#### notes

3) Cross Multiplication Method- To understand this method properly we shall take help of a example
4x+2y-7=0 ......eq1
5x+3y-8=0 ......eq2
While practicing this method if we want to find value of a particular variable we will take that variable as a numerator and the denominator will be the substraction between the cross multiplication of coefficients of the remaining two variables. Like in this case it will be like

x/"(2×-8)-(-7×3)"

y/"(4×-8)-(-7×5)"

1/"(4×3)-(2×5)"

All of them are equal to each other, so if you to find value of x then take,

x/"(2×-8)-(-7×3)" = 1/"(4×3)-(2×5)"

x/"-16+21"=1/"12-10"

x/5= 1/2

x=5/2

To find the value of y,

y/"(4×-8)-(-7×5)"= 1/"(4×3)-(2×5)"

y/"-32+35" = 1/"12-10"

y/3 = 1/2

y= 3/2

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### Shaalaa.com

Pair of Linear Equation in two variable part 14 (Algebraic Cross Multiplication) [00:12:42]
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