-5.8 - (-8.4)
When we multiply two negatives they become a positive. In this situation, where there is no other number, you can assume there's basically a 1 in that place.
-5.8 - 1(-8.4) would be just as correct. (If this helps visually clarify anything.)
So we take that -1 and multiply it by that -8.4. Multiplying 1 against anything leaves it the same, so we just need to change the sign. Two negatives make a positive.
-5.8 + 8.4
Now we add these together.
This gives us our final answer of 2.6
3 3/6 is the same as 3 1/2, so 23 take 3 is 20. 20 take 1/2 is 19 1/2.
FOLLOW ME FOR CLEARING YOUR NEXT DOUBT
We can write and solve the differential equation that fits the statement given;
dy/dt = k(50-t)
∫dy = ∫ k(50-t)dt
= ∫ (50k - kt) dt
therefore;
y = 50kt - k/2(t²) + C
Alternatively, can be written as
y = - k/2 (50-t)² + C)
Notice the 7) 1st sequence, and the 8) second one