Question

Richard was thinking of a number. Richard adds 3, then divides by 4 to get an answer of -4.

What was the original number?

Answer 1

Let the unknown number be x

x + 3

------- = - 4

4

Multiply both sides of the equation by 4

x +3 = -16

Move constant to the right and change its sign

x= -16 - 3

calculate the difference

x= -19

Hope it helps :)

Explanation:

Answer 2

Explanation:

Let's call Richard's number X.

Richard starts with X. Adds 3. Divides by 4. Lands on -4.

x +3 /4 =-4

x+3/4= -4

You need to isolate the x. Move the numbers to the other side. Remember anything you do on one side of the equals you have to do on the other side.

To move them, you do the opposite. It wants to divide by four, so you should multiply by four on both sides.

x+3/4X4= -4X4

We know that-4X4= -16, and the divide by 4 times 4 cancel out, so we will plug that in.

x+3= -16

The opposite of +3 is -3, so...

x+3-3= -16-3

+3-3+0 and -16-3= -19

x=-19

Richard's original number was -19.