Question

If 21 more than 3 times a number is -15 , what is the number?

A: 2
B: -12
C: -2
D: 12

Answer 1

Let X = the number.

You have 21 more than 3 times the number which is:

3x +21 = -15

Subtract 21 from both sides:

3x = -36

Divide both sides by 3:

x = -36 /3

x = -12

The answer is B.

Answer 2

Answer:

-13

Explanation:

Rewrite Equation:

(3 · x) + 21 = -15

Subtract 21 From Both Sides:

(3 · x) + 21 - 21 = -15 - 21

Simplify:

3x = -36

Divide Both Sides By 3:

$\bold{\frac{3x}{3} \ = \ \frac{-36}{3} }$

Simplify:

x = -12

Mordancy.