Answer:
Part 1) The engine speed that maximizes torque is 
Part 2)The maximum torque is 
Step-by-step explanation:
<u><em>The correct equation is</em></u>

This is the equation of a vertical parabola open downward (because the leading coefficient is negative)
The vertex represent a maximum
The x-coordinate of the vertex represent the engine speed that maximizes torque
The y-coordinate of the vertex represent the maximum torque
Solve the quadratic equation by graphing
using a graphing tool
The vertex is the point (3.093,74.683)
see the attached figure
therefore
The engine speed that maximizes torque is
---> because is in thousands of revolutions per minute
The maximum torque is

Y varies directly with x" means y = constant * x or y = kx ----- (1)1. when x = -1/2, y = 2Put it in (1):2 = k * (-1/2)multiply by 2:4 = k * (-1)4 = -kk = -4y = -4x
"find the value of y when x= -0.3"y = -4x = (-4) * (-0.3) = 1.2
So for each problem, start with y = kxThey give you one x and one y value.Put it in y = kx and find k.Then put x = -0.3 and find y.
Answer:
78
Step-by-step explanation:
Adult tickets = x
Child tickets = 3(Adult tickets) = 3x
The cost of child admission is $5.50, and the cost of adult admission is $8.80. Multiply the cost of admission by the variables and set equal to the total sales.
8.8(x) + 5.5(3x) = 663.6
8.8x + 16.5x = 663.6
25.3x = 663.6
x = 26
Child tickets = 3x
Child tickets = 3(26)
Child tickets = 78
78 child tickets were sold that day.
I don't know what you are asking but my best guess is it will be
$4.46 in total
❀ 

To solve, use the algebraic identity ➺
- <u>(x + a)( x + b) = x² + (a + b)x + ab</u>

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