Question

Solve by elemination method x-3y = 10 and x - 7y= -30

Answer 1

Step-by-step explanation:

×-3y=10

×-7y=-30

- + +

4y=40

y=10

×-3×10=10

×=40

Answer 2

$\underline{\underline{\mathfrak{\green{Answer:-}}}}$

x = 40

y = 10

$\underline{\underline{\mathfrak{\green{Explanation:-}}}}$

Given:

Pair of linear equations are-

x-3y = 10 and x-7y = -30

To Find:

values of x and y

Solution:

Let,

$\mathsf{x-3y = 10 -------(1) }$

$\mathsf{x-7y = -30 -------(2)}$

Now, eq.(1) - (2)

$\mathsf{(x-3y)-(x-7y) = 10-(-30)}$

$\mathsf{x-3y-x+7y = 10+30}$

$\mathsf{4y = 40}$

$\mathsf{y = \dfrac{40}{4}}$

$\mathsf{y = 10}$

By sub. value of "y" in eq.(1)

$\mathsf{x-3(10) = 10}$

$\mathsf{x-30= 10}$

$\mathsf{x = 10+30}$

$\mathsf{x = 40}$

_____________________

$\underline{\underline{\mathfrak{\red{Verification:-}}}}$

Let us substitue the values of 'x' and 'y' in eq.(1)

$\mathsf{x-3y = 10}$

$\mathsf{40-3(10) = 10}$

$\mathsf{40-30 = 10}$

$\mathsf{10= 10}$

Now, substitue the values of 'x' and 'y' in eq.(2)

$\mathsf{x-</strong><strong>7</strong><strong>y</strong><strong> = </strong><strong>-</strong><strong>3</strong><strong>0</strong><strong>}$

$\mathsf{40-7(10) = -30}$

$\mathsf{40-70 = -30}$

$\mathsf{-30 = -30}$

Hence, the values of 'x' and 'y' are 40 and 10 respectively!