three times the sum of a number and 4 is equal to -9. find that number

Answer 1

3 * (x + 4) = -9

the goal is to get the x by itself. To do that, you do the same operation (multiply, divide, add, or subtract) to both sides. You can do multiple operations to get x by itself. It's illustrated below

OPERATION 1 - Division

(3(x + 4)) / 3 = ( -9) / 3 divide both sides by 3 to get rid of the "3 *" in "3 * (x + 4)"

x + 4 = -3 since the 3's cancelled out, -9/3 = -3 therefore x + 4 = -3

OPERATION 2 - Subtraction

x + 4 - 4 = -3 - 4 subtract 4 from both sides to get rid of the "+ 4" in "x + 4"

x = -3 - 4 = -7 therefore x = -7 or the number you wanted to find was -7