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.)
Are you looking for the amount after interest gained? If so I believe the answer would be $40.
500 x 0.04 x 2 = 40
Let the numbers be a and b, then ab=0.2 and a/b=0.8, so a=0.8b. Therefore, 0.8b^2=0.2 and b^2=0.2/0.8=2/8=1/4 and b=+1/2 or +0.5 and a=+0.8*0.5=+<span>0.4. The two numbers are therefore 0.5 and 0.4 or -0.5 and -0.4. The quotient is 0.4/0.5</span>
Answer:
The 3rd one
Step-by-step explanation: