Jean's scores on the first three of four 100-point tests were 82, 86, and 91. what score must she receive on the fourth test to
1 answer:
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Answer:
Step-by-step explanation:
The formula that is used to calculate the area of a rectangle is:
Where "l" is the lenght and "w" is the width.
You know that the area of that rectangle is:
And, according to the exercise, its lenght is 7 more than its width; then:
Then, you can make the corresponding substitution into the formula :
Simplify:
Factor the equation. Find two numbers whose sum is 7 and whose product is -744. These are 31 and -24.
Then, you get:
The width of the rectangle is the positive value:
Then, the lenght is:
Answer:
a = 2, b = - 5
Step-by-step explanation:
Given
y = ax² + bx
is the measure of the slope at x = a
Differentiate each term with respect to x using the power rule
(a
) = na
= 2ax + b, hence
2ax + b = 3 at (2, - 2)
Substitute x = 2 into
4a + b = 3 → (1) and substitute x = 2 into y
4a + 2b = - 2 → (2)
Subtract ( 1) from (2)
b = - 2 - 3 = - 5
Substitute b = - 5 into (1)
4a - 5 = 3 ( add 5 to both sides )
4a = 8 ( divide both sides by 4 )
a = 2