Question

Solve x+y=8 and 2x-y=1 by
substitutional method​

Answer 1

Step-by-step explanation:

$\sf\underline\red{Given~:-}$

• x + y = 8 → ①
• 2x - y = 1 → ②

$\sf\red{From~eqn~①~}$ ,

• x + y = 8
• x = 8 - y → Eqn 1

Now ,

$\sf\red{ Substitute~x~value~in~eqn~2}$

• 2x - y = 1
• 2 ( 8 - y ) - y = 1
• 16 - 2y - y = 1
• 16 - 3y = 1
• - 3y = 1 - 16
• - 3y = - 15

$\green{arrow}$ Cancel ${~-~}$ on both sides

• 3y = 15
• y = $\frac{15}{3}$
• y = 5

$\sf\red{Put~y~value~in~eqn~1~}$

• x = 8 - y
• x = 8 - 5
• x = 3

:. x = 3 and y = 5