Math, asked by chinnughanamukhi73, 4 months ago

solve by substitution method
X+y=18, x-y=4​

Answers

Answered by Bᴇʏᴏɴᴅᴇʀ
13

Answer:-

\red{\bigstar}\large\boxed{\tt\purple{x = 11}}

\red{\bigstar}\large\boxed{\tt\purple{y = 7}}

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Given:-

  • x + y = 18

  • x - y = 4

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To Find:-

  • Value of x and y.

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Solution:-

\sf x + y = 18 \dashrightarrow\bf\red{[eqn.i]}

\sf x - y = 4 \dashrightarrow\bf\red{[eqn.ii]}

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Taking eqn.[i]:-

\sf x + y = 18

\sf x = 18 - y \dashrightarrow\bf\red{[eqn.iii]}

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Substituting eqn.[iii] in eqn.[ii]:-

\sf x - y = 4

\sf (18-y) - y = 4

\sf 18 - y - y = 4

\sf 18 - 2y = 4

\sf - 2y = 4 - 18

\sf - 2y = - 14

\sf y = \dfrac{-14}{-2}

\large{\bf\pink{y = 7}}

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Substituting value of y in eqn.[i]:-

\sf x + y = 18

\sf x + 7 = 18

\sf x = 18 - 7

\large{\bf\pink{x = 11}}

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Therefore, value of x = 11 and y = 7.

Answered by Flaunt
41

\huge\bold{\gray{\sf{Answer:}}}

Explanation:

Given :

X+y=18.......(1)

and x-y=4........(2)

To Find :

x and y values

______________________________________________

From Equation(1)

We find substitute for x and put into Equation2

x + y = 18

x = 18 - y........(3)

Put X's value into Equation2

 =  > x - y = 4

 =  > (18 - y) - y = 4

 =  > 18 - 2y = 4

 - 2y = 4 - 18

 =  >  - 2y =  - 14

y =  \frac{ - 14}{ - 2}  = 7

\bold{\boxed{\red{y = 7}}}

Now ,put Y's value into Equation1

x = 18 - y

x = 18 - 7 = 11

\bold{\boxed{\pink{x = 11}}}

Check:-

x + y = 11 +  = 18

x - y = 11 - 7 = 4

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