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3 years ago

I am confused on how to do this

Mathematics

1 answer:

babymother [125]3 years ago

4 0

So, u would start by expanding the bracket and ignoring the 2 at the moment.
(x+9)(x+9)= x^2-18x+81(using the foil method!

Then u would put 2 at the front to get:
2(x^2+18x+81)
= 2x^2+36x+162

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Factor completely 2x^2 +6x -108

never [62]

Answer:

2(x-6)(x+9)

Step-by-step explanation:

5 0

3 years ago

1)A student earned a grade of 80% on a math test that had 60 problems. How many

FrozenT [24]

Answer:

Step-by-step explanation:

80% = .8

60 x .8 = 48

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2 years ago

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Physics students drop a ball from the top of a 100 foot high building and model its height as a function time with the equation

pishuonlain [190]

When the ball hits the ground, the height is 0.

0 = 100 - 16t²

0 = (10 - 4t)(10 + 4t)

0 = 10 - 4t or 0 = 10 + 4t

4t = 10 or -4t = 10

t = $\frac{10}{4}$ or t = $-\frac{10}{4}$

Time cannot be negative (unless you have a time machine) so disregard $-\frac{10}{4}$

Answer: t = $\frac{5}{2}$ = 2.5 seconds

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2 years ago

A bridge is built in the shape of a parabolic arch. The bridge arch has a span of 166 feet and a maximum height of 40 feet. Find

scoray [572]

Answer:

38.27775 feet

Step-by-step explanation:

The bridge has been shown in the figure.

Let the highest point of the parabolic bridge (i.e. vertex of the parabola) be at the origin, $O(0,0)$ in the cartesian coordinate system.

As the bridge have the shape of an inverted parabola, so the standard equation, which describes the shape of the bridge is

$x^2=4ay\;\cdots(i)$

where $a$ is an arbitrary constant (distance between focus and vertex of the parabola).

The span of the bridge = 166 feet and

Maximum height of the bridge= 40 feet.

The coordinate where the bridge meets the base is $A(83, -40)$ and $B(-83, -40).$

There is only one constant in the equation of the parabola, so, use either of one point to find the value of $a$ .

Putting $A(83,-40)$ in the equation (i) we have

$83^2=4a(-40)$

$\Rightarrow a=-43.05625$

So, on putting the value of $a$ in the equation (i), the equation of bridge is

$x^2=-172.225y$

From the figure, the distance from the center is measured along the x-axis, x coordinate at the distance of 10 feet is, $x=\pm 10$ feet, put this value in equation (i) to get the value of y.