Choices "a" and "c" will form triangles
Answer:

Step-by-step explanation:

Answer:
In the equation, it divides 21 by x before knowing what x is, and gets it incorrect. Instead, you need to divide 21 by -4.2.
Step-by-step explanation:
-4.2x = 21
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-4.2
x = -5
The answer is b. 2. It is 2, because -10 plus 4 is -6. Then -6 plus 8 is 2.