Answer: - 6 & - 3
Explanation:
This 1) First start off by listing the multiplication partners of 18:
1*18
2*9
3*6
2) Now take away add the two partners of every multiplication partner you have like this:
1+18= 19
2+9=11
3+6= 9
3) Determine which one is equal to 9 but multiplies to 18 as you can see 3*6 is the option however in the problem you have to have -9 so here are some rules:
2 negatives times each other will equal a positive number
2 negatives plus each other will equal a negative number
4) From this information you can conclude that you can use -6 & -3 because:
-6*-3 = 18
(-6) + (-3) = -9