Question

X+y=15 x+y=3 solve the following questions in substitution determinant and eliminations method

Answer 1

$\large{\underline{\underline{\sf{\blue{Correct \: Question-}}}}}$

• x + y = 15 .... (1)

• x - y = 3 .... (2)

$\large{\underline{\underline{\sf{\pink{To \: Find-}}}}}$

• Values of x & y.

$\large{\underline{\underline{\sf{\orange{Solution-}}}}}$

Subtracting equation (1) from equation (2),

$\mathtt{x {\cancel{+ y}} = 15 \: .... \: (1)} \\ \\ \mathtt{x {\cancel{- y}} = 3 \: .... \: (2)} \\ ............................... \\ \mathtt{2x = 18}$

$:\implies\mathtt{2x = 18} \\ \\ :\implies\mathtt{x = \dfrac{\cancel{18}}{\cancel{2}}} \\ \\ \boxed{:\implies\mathfrak\red{x = 9}}$

Substituting x = 9 in equation (1),

$:\implies\mathtt{x + y = 15 \: .... \: (1)} \\ \\ :\implies\mathtt{9 + y = 15} \\ \\ :\implies\mathtt{y = 15 - 9} \\ \\ \boxed{:\implies\mathfrak\green{y = 6}}$

Therefore,

$\sf\star \: \underbrace\purple{x \: = \: 9 \: , \: y \: = \: 6} \: \star$

Hence,

• Values of x & y are 9 & 6.

Answer 2

$\huge{\underbrace{\sf{\purple{Appropriate\:Question}}}}$

x + y = 15, x - y = 3 solve the following questions in substitution determinant and elimination method.

$\huge{\underbrace{\sf{\pink{Required\:Answer:}}}}$

:$\implies{\sf{x+y=15\:\:\:\:\:\:\:....(1)}}$

:$\implies{\sf{x-y=3\:\:\:\:\:\:\:....(2)}}$

• We can write eq(1) as $\displaystyle{\sf{x=15-y}}$
• Substitute the value of x in eq(2)

:$\implies{\sf{(15-y)-y=3}}$

• Solve the equation.

:$\implies{\sf{15-y-y=3}}$

:$\implies{\sf{15-2y=3}}$

:$\implies{\sf{15+3=2y}}$

:$\implies{\sf{18=2y}}$

:$\implies{\sf{y= \dfrac{18}{2}}}$

:$\large\implies{\boxed{\sf{\orange{y=9}}}}$

Hence,the value of y is 9.

• Substitute the value of y in eq(1).

:$\implies{\sf{x+y=15}}$

:$\implies{\sf{x+9=15}}$

:$\implies{\sf{x=15-9}}$

:$\large\implies{\boxed{\sf{\orange{x=6}}}}$

Hence, the value of x is 6.

___________________

$\huge{\underline{\sf{\pink{More\:To\:Know!}}}}$

◾️What is Elimination by Substitution Method ?

The method in which the elimination of the variable can be performed by substituting the value of another variable in an equation is called Elimination by Substitution Method.

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