70% of what number is 21 and how do you do it

70 % of unknown number = 21
We multiply the percentage by a variable and make it = to the given value.
70% of n = 21
Change percent to decimal
70% =  = 0.7
0.7n = 21
divide either sides by 0.7 to isolate n

= 
0.7 and 0.7 cancels out
n = 30

0.7 × 30 = 21
70 % of 30 is 21
An example has been attached below

% of a number = multiply % by number
value is the % of a number = divide % by value

  b.   the average rate of change of f(x) is less than the average rate of change of g(x).

step-by-step explanation:

since the length of the interval is the same in each case, we only need to compare the change in y-value to see which is greater.

f(-2) = -3f(1) = 6 . . . estimated from f(x) = (x+2)^2-3, which matches points on the graph (-1,-2) and (0, 1)

so the change in y-value for function f is (6 )) = 9.

the table tells us

g(-2) = 1g(1) = 31

so the change in y-value for function g is (31 -1) = 30.

the change in y-value of f(x) on the interval is less than the change in y-value of g(x) on the same interval, so the average rate of change of f(x) is less than the average rate of change of g(x).

The slope best fit isc. 1/6 mile per hour