all of them except the last efg and bcd
In mathematical notation, ∑ means summation. So wherever you see the symbol, you have to sum over all elements in the set. Let's solve the question.
a. ∑m means, to sum all elements in the set m: ∑m = 12 + 15 + 20 + 30 = 77
b. ∑
means to sum all elements in the set f as the square of the elements f = 
c. ∑mf means to sum all elements as the product of the elements of m and f = (12×5) + (15×9) + (20
10) + (30×16) = 875
d. ∑
means to sum all elements as the product of the square of m and f = 
Answer:
Josh is wrong.
Step-by-step explanation:
5^-x / 5^x = 5^(-x-x) = 5^-2x
= 1 / 5^2x
(you subtract the exponents when dividing )
So Josh is wrong ( he would be correct if we were multiplying)
Answer:
Simplified expression is 1.8i+0.6s
Step-by-step explanation: