How would you solve this?

Write down the quadratic equation whose roots are $x = -7$ and $x = 1,$ and the coefficient of $x^2$ is 1. Enter your answer in

pav-90 [236]

<h2>Steps:</h2>

So firstly, since we know that the coefficient of x² is 1, this means that this is our base equation:

y = x² + bx + c

Now, since we know that the roots are -7 and 1, set y = 0 and set x = -7 and 1 and simplify:

$0=(-7)^2+b(-7)+c\\0=49-7b+c\\-49=-7b+c\\\\0=1^2+b(1)+c\\0=1+b+c\\-1=b+c\\\\-49=-7b+c\\-1=b+c$

Now with this, we can set up a system of equations to solve for b and c. For this, I will be using the elimination method. For this, subtract the 2 equations:

$\begin{alignedat}{2}-49&=-7b+c\\-(-1&=b+c)\\-48&=-8b\end{alignedat}$

Now that the c variable has been eliminated we can solve for b. For this, divide both sides by -8 and your first part of your answer is b = 6.

Now that we know the value of b, plug it into either equation to solve for c:

$-49=-7(6)+c\\-49=-42+c\\-7=c\\\\-1=6+c\\-7=c$

<h2>Answer:</h2>

<u>Putting it together, your final answer is x² + 6x - 7 = 0.</u>

4 0

3 years ago

If a 50 ft flagpole casts a 95 ft shadow, then how long is the shadow that a 5 ft tall of man casts ?

lesantik [10]

9.5 feet,to find that you must find out how many times longer the shadow of the pole is than the pole, and to do that you must divide 95 by 50, in which you get 1.9. And then to find the length of the shadow the man casts you must multiply his height by 1.9.

8 0

3 years ago

Find j(3x^4y^7) if j(n)=n^3

qaws [65]

Answer:

Step-by-step explanation:

Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :

3*x-(4*y-7)=0

STEP

1

:

Equation of a Straight Line

1.1 Solve 3x-4y+7 = 0

Tiger recognizes that we have here an equation of a straight line. Such an equation is usually written y=mx+b ("y=mx+c" in the UK).

"y=mx+b" is the formula of a straight line drawn on Cartesian coordinate system in which "y" is the vertical axis and "x" the horizontal axis.

In this formula :

y tells us how far up the line goes

x tells us how far along

m is the Slope or Gradient i.e. how steep the line is

b is the Y-intercept i.e. where the line crosses the Y axis

The X and Y intercepts and the Slope are called the line properties. We shall now graph the line 3x-4y+7 = 0 and calculate its properties

Graph of a Straight Line :

Calculate the Y-Intercept :

Notice that when x = 0 the value of y is 7/4 so this line "cuts" the y axis at y= 1.75000

y-intercept = 7/4 = 1.75000

Calculate the X-Intercept :

When y = 0 the value of x is -7/3 Our line therefore "cuts" the x axis at x=-2.33333

x-intercept = -7/3 = -2.33333

Calculate the Slope :

Slope is defined as the change in y divided by the change in x. We note that for x=0, the value of y is 1.750 and for x=2.000, the value of y is 3.250. So, for a change of 2.000 in x (The change in x is sometimes referred to as "RUN") we get a change of 3.250 - 1.750 = 1.500 in y. (The change in y is sometimes referred to as "RISE" and the Slope is m = RISE / RUN)

Slope = 1.500/2.000 = 0.750

Geometric figure: Straight Line

Slope = 1.500/2.000 = 0.750

x-intercept = -7/3 = -2.33333

y-intercept = 7/4 = 1.75000

4 0

3 years ago

How many five-card hands (drawn from a standard deck) contain exactly three fives? (A five-card hand is any set of five differen

VashaNatasha [74]

Answer:

4512.

Step-by-step explanation:

We are asked to find the number of five-card hands (drawn from a standard deck) that contain exactly three fives.

The number of ways, in which 3 fives can be picked out of 4 available fives would be 4C3. The number of ways in which 2 non-five cards can be picked out of the 48 available non-five cards would be 48C2.

$4C3=\frac{4!}{3!(4-3)!}=\frac{4*3!}{3!*1}=4$