Each piece is 7 and 1/3 feet long (7 feet 4 inches)
Answer:
19
Step-by-step explanation:
The opposite sides are equal, so:
PS = 3y+1
RS = 4y+2
QR = 3y+1
PQ = 4y+2
Therefore, we can set the perimeter 90 = PS+RS+QR+PQ
90 = (3y+1) + (4y+2) + (3y+1) + (4y+2), or,
90 = 2(3y+1) + 2(4y+2)
90 = 6y+2 + 8y+4
90 = 14y + 6
84 = 14y
y = 6
Then, we go back to the question. It's asking for the length of PS. PS = 3y+1, so we plug in 6 for y
3(6)+1
18 + 1 = <u>19</u>
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The function, as presented here, is ambiguous in terms of what's being deivded by what. For the sake of example, I will assume that you meant
3x+5a
<span> f(x)= ------------
</span> x^2-a^2
You are saying that the derivative of this function is 0 when x=12. Let's differentiate f(x) with respect to x and then let x = 12:
(x^2-a^2)(3) -(3x+5a)(2x)
f '(x) = ------------------------------------- = 0 when x = 12
[x^2-a^2]^2
(144-a^2)(3) - (36+5a)(24)
------------------------------------ = 0
[ ]^2
Simplifying,
(144-a^2) - 8(36+5a) = 0
144 - a^2 - 288 - 40a = 0
This can be rewritten as a quadratic in standard form:
-a^2 - 40a - 144 = 0, or a^2 + 40a + 144 = 0.
Solve for a by completing the square:
a^2 + 40a + 20^2 - 20^2 + 144 = 0
(a+20)^2 = 400 - 144 = 156
Then a+20 = sqrt[6(26)] = sqrt[6(2)(13)] = 4(3)(13)= 2sqrt(39)
Finally, a = -20 plus or minus 2sqrt(39)
You must check both answers by subst. into the original equation. Only if the result(s) is(are) true is your solution (value of a) correct.
The answer is X is equal to 1.4
