Ashley spent 20 minutes typing a 3,000 word essay. What’s her speed I’m words per minute?
2 answers:
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Answer:
- width: 18 in
- length: 27 in
Step-by-step explanation:
The relations between length (L) and width (W) are ...
W +9 = L
LW = 486
Substituting gives ...
(W+9)W = 486
W^2 +9W -486 = 0 . . . put in standard form
(W +27)(W -18) = 0 . . . . factor
W = 18 . . . . the positive solution
The width of the rectangle is 18 inches; the length is 27 inches.
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<em>Comment on factoring</em>
There are a number of ways to solve quadratics. Apart from using a graphing calculator, one of the easiest is factoring. Here, we're looking for factors of -486 that have a sum of 9.
486 = 2 × 3^5, so we might guess that the factors of interest are -2·3² = -18 and 3·3² = 27. These turn out to be correct: -18 +27 = 9; (-18)(27) = -486.
Answer:
f(0.1) =
Step-by-step explanation:
Plug x = 0.1.
Therefore f(0.1) = ln (log (0.1)).
0.1 = 10^(-1), and by the definition of log, log 0.1 = -1.
Now f(0.1) = ln (-1).
By Euler's identity, e^(i pi) = -1.
So ln (-1) would be i pi.
f(0.1) =