The answer is A because Alon could have rotated the figure and discovered that they are congruent
(2x+1)+(3x-5)=5x-4 you just have to try some of them out and see which ones work
18.
-2(-9)+3
18+3
21
Explanation: -2(-9) When multiplying numbers that have both a negative sign, the answer is positive. Multiply normally.
19.
-6(-4)0
24(0)
0
Explanation: -6(-4) As I explained before, the answer would be positive.
24(0) Every number multiplied by 0 is 0.
20.
56+(-7)
49
Explanation: 56+(-7) Any problem like this is just basically going to be 56-7.
21.
-36+(-4)
-40
Explanation: -36+(-4) You are simply adding normally then adding the sign. This will only work if the signs are the same. (Signs are positive and negative.)
The sample space has 36 possible pairs from 1,1 1,2 1,3 up to 6,5 and 6,6
(a). Three pairs add to 4 1,3 2,2 and 3,1 so P(4) = 3/36 = 1/12
(b). 6 pairs add to 7 so P(7) = 6/36 = 1/6
(c) 15 pairs add to less than 7 so P(<7) = 15/36 = 5/12
