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`
Video Tutorials
Shaalaa.com | Pair of Linear Equation in two variable part 14 (Algebraic Cross Multiplication)
Series 1: playing of 3
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