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Question 709406: please help me solve this question.
when 3 is added to a number and the result is multiplied by 5 , you obtain one less than the number you started with .what is that number ?
Answer by josh_jordan(263)   (Show Source):
You can put this solution on YOUR website! To solve, we need to convert the word problem into a mathematical formula. Let's examine the first part of the sentence before the comma:
"When 3 is added to a number and the result is multiplied by 5" - In other words, (3 + x) * 5, where x represents the unknown number
"you obtain one less than the number you started with" - In other words, x - 1.
So, when we put these two parts of the sentence together, we are left with
(3 + x) * 5 = x - 1
Now, we can solve for x.
First, using the distributive property of multiplication, we can multipy the 5 by everything in the parenthesis:
5*3 + 5*x -----> 15 + 5x
We are left with
15 + 5x = x - 1
We now need to get x all by itself on one side of the equal sign, and place the numbers on the other side of the equal sign. To do so, first subtract x from both sides of the equal sign, giving us
15 + 5x - x = x - x - 1 -----> 15 + 4x = -1
Next, subtract 15 from both sides of the equation, giving us
15 - 15 + 4x = -15 - 1 -----> 4x = -16
Finally, dividing both sides of the equation by 4, will leave us with x one on side of the equal sign, and our unknown number on the other side:
 -----> x = -4
Therefore, the number is -4
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