## InspectorJoe one year ago need help solving this factoring problem. M^2-M-90

1. anonymous

so we have to find what adds to -1 and multiplies to -90.

2. inspectorjoe

correct

3. inspectorjoe

I tried both -90 or otherwise -1 but I was wrong on the -1

4. jdoe0001

hint: $$\begin{array}{cccllll} M^2&-M&-90\\ &\uparrow &\uparrow \\ &9-10&9\cdot -10 \end{array}$$

5. inspectorjoe

but I though on the problem I would have to have one + and one _ at the end inside the ( ) ( )

6. inspectorjoe

because of the rules

7. inspectorjoe

yes I just got sorry thanks