Question

Select the correct answer.
Solve the system of equations given below.
-5x=y-5
-2y=-x-21
A.
(10,16)
B.
(10,-45)
C.
(-1,-23)
D.
(-1,10)

if right will mark b

Answer 1

Answer:

b is the Answer

Step-by-step explanation:

b is the Answer

Answer 2

The correct answer to the system of equations is (D) ( -1, 10 ).

Given: The equations -5x = y - 5 and -2y = - x - 21.

To Find: The correct answer.

Solution:

• Whenever we are given a two-equation and we are required to solve it, we shall do so to obtain the values of two unknown variables.

• We can solve such a pair of equations by substitution method or elimination method.

• In this numerical, we shall use the substitution method to find the value of x and y.

• In the substitution method, we shall find an expression in the form of x from the first equation and put it in the second equation to calculate the value of 'y'. Again we shall put this value of y in any of the equations to find the value of 'x'.

Coming to the numerical, we are given;

The equations:

                - 5x = y - 5                                                           ...(1)

                - 2y = - x - 21                                                        ...(2)

From (1), we shall make x as the subject;

                - 5x = y - 5            

            ⇒ 5x = 5 - y

            ⇒  x  =  ( 5 - y ) / 5                                                ...(3)

Putting (3), in (2) we get;

                  - 2y = - x - 21          

             ⇒  - 2y = - [( 5 - y ) / 5 ] - 21

             ⇒  10y = 5 - y + 105

             ⇒  11y = 110

             ⇒  y = 110 / 11

             ⇒  y = 10

Putting y = 10 in (1), we get;

                   - 5x = y - 5  

              ⇒  - 5x = 10 - 5

              ⇒  - 5x = 5

              ⇒  x = - 1

Hence, we can say that ( x, y ) = ( -1, 10 ).

The correct answer to the system of equations is (D) ( -1, 10 ).

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