Question

Which of the following would not be the result of a substitution in the following system?
2x + y = 7
y - x= 1

A. 7 - 2x- x = 1

B. 2x + x + 1 = 7

C. 2(y + 1) + y = 7​

Answer 1

Hello!

The correct option is:

C. $2(y+1)+y=7$

Why?

To find which of the given options are not the result of a substitution in the given system, we need to isolate the variable in function of the other variable, and then substitute it.

So, substituting and discarding, we have:

- First equation:

$2x+y=7$

Isolating "y", we have:

$y=7-2x$

Then, substituting it into the second equation, we have:

$y-x=1$

$7-2x-x=1$

We have that it's a result of a substitutiong in the following system (option A)

- Second equation:

$y-x=1$

Isolating "y", we have:

$y=x+1$

Then, substituting it into the first equation, we have:

$2x+y=7$

$2x+(x+1)=7[/tex

[tex]2x+x+=7[/tex

We have that it's a result of a substitution in the following system (option B)

Hence, we have that the option C is not a result of a substitution in the given system of equations since there is not a possible value of the variable "x" that is equal "y+1".

So, the correct option is:

C. [tex]2(y+1)+y=7$

Have a nice day!

Answer 2

Answer:

C. 2(y + 1) + y = 7​

Step-by-step explanation: