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If
<em>f(x)</em> = <em>ax</em> ³ + <em>bx</em> ² - 5<em>x</em> + 9
then
<em>f '(x)</em> = 3<em>ax </em>² + 2<em>bx</em> - 5
Given that <em>f</em> (-1) = 12 and <em>f</em> '(-1) = 3, we get the system of equations
-<em>a</em> + <em>b</em> + 5 + 9 = 12
3<em>a</em> - 2<em>b</em> - 5 = 3
or
-<em>a</em> + <em>b</em> = -2
3<em>a</em> - 2<em>b</em> = 8
Multiply through the first equation by 2 and add it to the second one to eliminate <em>b</em> and solve for <em>a</em> :
2(-<em>a</em> + <em>b</em>) + (3<em>a</em> - 2<em>b</em>) = 2(-2) + 8
-2<em>a</em> + 2<em>b</em> + 3<em>a</em> - 2<em>b</em> = -4 + 8
<em>a</em> = 4
Substitute this into the first equation above to solve for <em>b</em> :
-4 + <em>b</em> = -2
<em>b</em> = 2
Answer:
53 1/3 km/h
Step-by-step explanation:
The car is going at 80km in 1.5 hours, so if you divide that value you get 26 2/3 km for every half hour, now you would want to multiply this times 2 to find the value for every hour, so then this would give you the answer 53 and 1/3 kilometers per hour.
Answer:
HB = 13
Step-by-step explanation:
In triangle GHJ, points A, B, C are mid points of the sides GH, HJ, GJ respectively.
Therefore by Mid-segment Theorem.

Answer: 16,000 students
Step-by-step explanation:
8/20 = x/40,000
20 * x = 8 * 40,000
x = (8 * 40,000)/20
x = 16,000 students