Question

12. which equation is an identity?
A. 7 - (9x + 3)= -9x - 4
B. 6m - 5 = 7m + 5 - m
C. 10p + 6 - p= 12p - 3(p-2)
D. 3y + 2=3y - 2

13. which equation has no solution?
A. 5v + 3 = 5v - 5
B. 2x - 4 = 2x + 7 - x
C. 2y + 5 - y= 2y - 3(y-6)
D. 7z + 9 = -7z -6

Answer 1

12.) c.

13.) a.

Answer 2

Solve each equation.
If the variables cancel out, and you get a true statement, it is an identity.
If the variables cancel out, and you get a false statement, it has no solution.

Answer 3

Let's do choice A in problem 12 together.
7 - (9x + 3)= -9x - 4
Distribute the negative sign on the left side:
7 - 9x - 3 = -9x - 4
Combine like terms:
4 - 9x = -9x - 4
Add 9x to both sides:
4 = -4
The variables canceled out, and we got a false statement.
That means choice A has no solution.