The function is a parabola which opens downwards.
-x^2 - 2x + 15
-(x^2 + 2x) + 15
= -[(x + 1)^2 - 1 ]+ 15
= -(x + 1)^2 + 16
The domain is all real numbers and the range is {y|y <= 16}
Its the second choice.
Let the cost of petrol of the car be £ x
£x=580mile
33.5mile=1gallon
1gallon=4.55litre
1litre=£1.09
By using chain rule,
X x33.5x1x1=580x1x4.55x1.09
Or,x=85.86
So x=£85.86
Expected value E(x) = 0.6(200,000) + 0.2(100,000) - 0.2(200,000) = 120,000 + 20,000 - 40,000 = 100,000
Therefore, the expected value is $100,000, so the company should build the mousetrap.
The square root of 13+29 is <span>6.48074069841 but, you can simply put 6.4</span>
