Question

Lesson 3 Unit 7, Solving Systems Using Elimination Quiz

Answer 1

Answer:

2) A

3) B

4) C

5) A

6) C

Step-by-step explanation:

2) Lets add 2 equation together, we will find:

$7x-7x+5y-2y=19-16\\3y=3\\y=1$

If we put y value in the first equation:

$7x+5=19\\7x=14\\x=2$

It is A

3) Substation is the best way to solve the system.

Lets multiply first equation with 4:

$4y=2x$

Substitute 2x with 4y:

$4y+3y=28\\y=4$

and x=8

4) Again lets substitute 3x with -y:

$-y+2y=6\\y=6$

Therefore x=-2

Correct answer is C

5) None of real numbers is the solution of this system.

6) First lets multiply first equation with -1 and add equations together:

$y-y=-3x-x-5+1\\0=-4x-4\\x=-1\\y=-2$

It falls to III

The answer is C