Guys
anyway can anyone explain how to do 12. (a
just letter a

x = 3 seconds

Step-by-step explanation:

The time (x) at which the function reaches its maximum can be determined in couple of ways. If you know calculus, you differentiate the quadratic, set to 0 and solve: . If you do not yet know how to do that, you can just apply the following argument:

The expression will be non-positive for any x. The largest it can be is 0. So the entire function can be at most 23, or less. It is 23 only when and that happens exactly for x=3 (seconds).

As a third option, you can also use a formula for the maximum point of a parabola, but the formula is non-intuitive so I prefer to skip that.

m∠cdf = 43° , m∠gdf = 114°, m∠gde = 23°, m∠edh = 23° , m∠cdh = 157°

step-by-step explanation:

since, it is given that de bisects the angle gdh ⇒ de divides the angle gdh into two equal angles.

⇒ m∠gde = m∠edh

⇒ 8·x   - 1 = 6·x + 5

⇒ x = 3

so, m∠gde = 8·x - 1 = 23°

and m∠edh = 23°

now, it is given ∠cde is an straight angle so, m∠cde = 180°

⇒ m∠cdf + m∠fdg + m∠gde = 180°

⇒ 43° + m∠fdg + 23° = 180°

⇒ m∠fdg = 114°

again, m∠cde = m∠cdh + m∠edh = 180°

m∠cdh + 23° = 180°

⇒ m∠cdh = 157°

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.