How do you solve the following system? $2x + 3y = 11$ , $ - x + y = - 3$
Answer
559.2k+ views
Hint: There are two ways to solve this question. We will answer this question by substitution method. In this method we find one variable in terms of another variable. Then, we will put the value of this variable in the second equation to find the answer.
Complete solution:
In the above question, it is given that
$ \Rightarrow 2x + 3y = 11 - - - - - \left( 1 \right)$
$ \Rightarrow - x + y = - 3 - - - - - \left( 2 \right)$
Now we will find the value of x in terms of variable y from the first equation.
$ \Rightarrow 2x + 3y = 11$
Now transpose $3y$ to the right hand side.
$ \Rightarrow 2x = 11 - 3y$
Now divide both sides by $2$.
$ \Rightarrow x = \dfrac{{11 - 3y}}{2}$
Now we will put this value in equation $1$.
\[ \Rightarrow - \dfrac{{11 - 3y}}{2} + y = - 3\]
Now taking LCM in left hand side
\[ \Rightarrow \dfrac{{ - 11 + 3y + 2y}}{2} = - 3\]
\[ \Rightarrow - 11 + 5y = - 6\]
$ \Rightarrow 5y = 11 - 6$
$ \Rightarrow 5y = 5$
Now divide both sides by $5$
$ \Rightarrow y = 1$
Now, put this value of y in equation $2$.
$ \Rightarrow - x + 1 = - 3$
On transposing x in the right hand side and $ - 3$ in the left hand side.
$ \Rightarrow x = 1 + 3$
$ \Rightarrow x = 4$
Therefore, the value of x is $4$ and the value of y is $1$.
Note:
There is one more method to answer this question. The method name is elimination method. In this method we make the coefficient of one variable in both the equations the same by multiplying both the equations with required constant value. Then we will add or subtract the equations in order to eliminate the variable.
Complete solution:
In the above question, it is given that
$ \Rightarrow 2x + 3y = 11 - - - - - \left( 1 \right)$
$ \Rightarrow - x + y = - 3 - - - - - \left( 2 \right)$
Now we will find the value of x in terms of variable y from the first equation.
$ \Rightarrow 2x + 3y = 11$
Now transpose $3y$ to the right hand side.
$ \Rightarrow 2x = 11 - 3y$
Now divide both sides by $2$.
$ \Rightarrow x = \dfrac{{11 - 3y}}{2}$
Now we will put this value in equation $1$.
\[ \Rightarrow - \dfrac{{11 - 3y}}{2} + y = - 3\]
Now taking LCM in left hand side
\[ \Rightarrow \dfrac{{ - 11 + 3y + 2y}}{2} = - 3\]
\[ \Rightarrow - 11 + 5y = - 6\]
$ \Rightarrow 5y = 11 - 6$
$ \Rightarrow 5y = 5$
Now divide both sides by $5$
$ \Rightarrow y = 1$
Now, put this value of y in equation $2$.
$ \Rightarrow - x + 1 = - 3$
On transposing x in the right hand side and $ - 3$ in the left hand side.
$ \Rightarrow x = 1 + 3$
$ \Rightarrow x = 4$
Therefore, the value of x is $4$ and the value of y is $1$.
Note:
There is one more method to answer this question. The method name is elimination method. In this method we make the coefficient of one variable in both the equations the same by multiplying both the equations with required constant value. Then we will add or subtract the equations in order to eliminate the variable.
Recently Updated Pages
Find the greatest six digit number that is exactly class 8 maths CBSE

What is the time difference between India and Cana class 8 social science CBSE

Compare LPG and wood as fuels class 8 chemistry CBSE

In Indian rupees 1 trillion is equal to how many c class 8 maths CBSE

30 opposite words in English from a to z class 8 english CBSE

How many cubic feet equals to 1 unit sand class 8 maths CBSE

Trending doubts
What is BLO What is the full form of BLO class 8 social science CBSE

Citizens of India can vote at the age of A 18 years class 8 social science CBSE

Full form of STD, ISD and PCO

One cusec is equal to how many liters class 8 maths CBSE

What are the methods of reducing friction. Explain

What is the difference between rai and mustard see class 8 biology CBSE


