What is 25 times pi

How do I do this??? It's for my algebra test on Wednesday.

Novay_Z [31]

Hold up. Hee haw. Whoa!
Your first instinct was to multiply it out and get rid of the parentheses.
That's often a good instinct, but this time, it made things harder for you.

This is a good example of a rule you should consider:

   Before you do anything to anything, sit back, relax,
   LOOK at the problem, THINK about it, and plan your
   strategy. Decide what the solution might look like,
   and what you're going to do to the given information
   in order to move towards the solution.

You might look at this particular equation and ponder:

-- If I multiplied this thing out and got rid of the parentheses, it would
have x³ in it. So there are going to be 3 solutions.

-- If either factor is zero, then the equation is true.

-- One of the factors is 6x. Setting that to zero gives one solution: x=0.

-- The other two solutions come from setting (4x² - 4) = 0 .

-- That's the difference of 2 squares, so it's (2x + 2) (2x - 2) = 0

-- The other 2 solutions come from setting each of those factors to zero.

There you are. You got this far just by thinking, without even picking up
your pencil yet.

4 0

3 years ago

Read 2 more answers

How do I graph -3x+y > -1

Drupady [299]

You are right good luck

5 0

3 years ago

A small plane took 3 hours to fly 960 km from Ottawa to Halifax with a tail wind. On the return trip, flying into the wind, the

Rina8888 [55]

Answer:

Wind speed: $\rm 40\; km \cdot h^{-1}$ .
Speed of the plane in still air: $\rm 320\; km \cdot h^{-1}$ .

Step-by-step explanation:

This problem involves two unknowns:

wind speed, and
speed of the plane in still air.

Let the speed of the wind be $x \rm \; km \cdot h^{-1}$ , and the speed of the plane in still air be $y\rm \; km \cdot h^{-1}$ . It takes at least two equations to find the exact solutions to a system of two variables.

Information in this question gives two equations:

It takes the plane three hours to travel $\rm 960\; km$ from Ottawa to with a tail wind (that is: at a ground speed of $x + y$ .)
It takes the plane four hours to travel $\rm 960\; km$ from Halifax back to Ottawa while flying into the wind (that is: at a ground speed of $-x + y$ .)

Create a two-by-two system out of these two equations:

$\left\{ \begin{aligned}&3(x + y) = 960 && (1) \\ &4(-x + y) = 960 && (2) \end{aligned}\right.$ .

There can be many ways to solve this system. The approach below avoids multiplying large numbers as much as possible.

Note that this system is equivalent to

$\left\{ \begin{aligned}&4 \times 3 (x + y) = 4\times960 && 4 \times (1) \\ &3\times 4(-x + y) = 3\times 960 && 3 \times (2) \end{aligned}\right.$ .

$\left\{ \begin{aligned}&12 x + 12y = 4\times960 && 4 \times (1) \\ &- 12x + 12y = 3\times 960 && 3 \times (2) \end{aligned}\right.$ .

Either adding or subtracting the two equations will eliminate one of the variables. However, subtracting them gives only $1 \times 960$ on the right-hand side. In comparison, adding them will give $7 \times 960$ , which is much more complex to evaluate. Subtracting the second equation ( $3 \times (2)$ ) from the first ( $4 \times (1)$ ) will give the equation