Question

A number decreased by negative three is equal to -40. Write an equation and find the number.

Answer 1

"A number decreased by negative three".... how would you write that as an algebraic expression?

Answer 2

-40= x - -3?

Answer 3

Very good. Just put "()" around the -3, so that it isn't confusing. E.g.:

-40=x-(-3)

subtraction followed by a negative number is confusing, without the ()

Answer 4

Now solve. Simplify on the right hand side first. That you subtract a negative, you can change that to addition, right? so do that.

Then you just have one more step, to find x.

Answer 5

That = *when

Answer 6

So -x-43=0?