What two numbers multiply to 1/4 and add to -1?

Malik fulton's savings account has a principal of $1,640 with an apr of 6% simple interest. how much is in his account at the en

ella [17]

I=prt
I=1640*0.06*6/12=49.2
A=1640+49.2=1,689.2

8 0

3 years ago

Formulate the situation as a system of two linear equations in two variables. Be sure to state clearly the meaning of your x- an

slega [8]

Answer:

1) There were 33 $4,000 investors and 27 $8,000 investors.

2) The solution in x = 4, y = 9.

3) There were 24 nickels and 56 dimes.

Step-by-step explanation:

1) A lawyer has found 60 investors for a limited partnership to purchase an inner-city apartment building, with each contributing either $4,000 or $8,000. If the partnership raised $348,000, then how many investors contributed $4,000 and how many contributed $8,000?

I am going to say that:

x is the number of investors that contributed 4,000.

y is the number of investors that contributed 8,000.

Building the system:

There are 60 investors. So:

$x + y = 60$

In all, the partnership raised $348,000. So:

$4000x + 8000y = 348000$

I am going to simplify by 4000. So:

$x + 2y = 87$

Solving the system:

The elimination method is a method in which we can transform the system such that one variable can be canceled by addition. So:

$1)x + y = 60$

$2)x + 2y = 87$

I am going to multiply 1) by -1. So we have

$1)-x - y = -60$

$2)x + 2y = 87$

By addition, the x are going to cancel each other

$-x + x - y + 2y = -60 + 87$

$y = 27$

For x:

$x + y = 60$

$x = 60-y = 60-27 = 33$

There were 33 $4,000 investors and 27 $8,000 investors.

2) Solve the system by row-reducing the corresponding augmented matrix.

$2x + y = 17$

$x + y = 13$

This system has the following augmented matrix:

$\left[\begin{array}{ccc}2&1&17\\1&1&13\end{array}\right]$

To help the row reducing, i am going to swap the first with the second line:

$L1 L2$

So we have:

$\left[\begin{array}{ccc}1&1&13\\2&1&17\end{array}\right]$

Now, reducing the first column.

$L2 = L2 - 2L1$

So we have:

$\left[\begin{array}{ccc}1&1&13\\0&-1&-9\end{array}\right]$

Now we do:

$L2 = -L2$

And the matrix is:

$\left[\begin{array}{ccc}1&1&13\\0&1&9\end{array}\right]$

Now to reduce the second column, we do:

$L1 = L1 - L2$

$\left[\begin{array}{ccc}1&0&4\\0&1&9\end{array}\right]$ .

So the solution is:

x = 4, y = 9.

3) A jar contains 80 nickels and dimes worth $6.80. How many of each kind of coin are in the jar?

I am going to say that x is the number of nickels and y is the number of dimes.

Each nickel is worth 5 cents and each dime is worth 10 cents.

Building the system:

There are 80 coins in all:

$x + y = 80$

They are worth $6.80. So:

$0.05x + 0.10y = 6.80$

Solving the system:

$1)x + y = 80$

$2)0.05x + 0.10y = 6.80$

I am going to divide 1) by -10, so we can cancel y. So:

$1)-0.10x - 0.10y = -8$

$2)0.05x + 0.10y = 6.80$

Adding:

$-0.10x + 0.05x - 0.10y + 0.10y = -8 + 6.80$

$-0.05x = -1.2$ *(-100)

$5x = 120$

$x = \frac{120}{5}$

$x = 24$

Also

$x + y = 80$

$y = 80-x = 80-24 = 56$

There were 24 nickels and 56 dimes.

8 0

3 years ago

What is the equation of the line that is perpendicular to the given line and has an x-intercept of -3?

Anvisha [2.4K]

Answer:

$y=-\frac{3}{2}x-\frac{9}{2}$

Step-by-step explanation:

Let the equation of the perpendicular line is,

y = mx + b

where m = slope of the line

b = y-intercept

From the graph, slope of the line passing through (0, -1) and (3, 1),

m' = $\frac{y_2-y_1}{x_2-x_1}$

m' = $\frac{1+1}{3-0}$

m' = $\frac{2}{3}$

To get the slope (m) of this line we will use the property of perpendicular lines,

m × m' = (-1)

m × $\frac{2}{3}$ = -1

m = $-\frac{3}{2}$

Equation of the perpendicular line will be,

$y=-\frac{3}{2}x+b$

x-intercept of the line is (-3) therefore, point on the line is (-3, 0)

0 = $-\frac{3}{2}(-3)+b$

b = $-\frac{9}{2}=-4.5$

Equation of the line will be,

$y=-\frac{3}{2}x-\frac{9}{2}$

3 0

3 years ago

Mean and standard deviation of sample proportions

asambeis [7]

Answer: D

Suppose that 35\%35%35, percent of students in a school can sing their national anthem correctly. The music teacher takes an SRS of 303030 students from the population of 750750750 students at the school and finds that 40\%40%40, percent of students sampled can sing their national anthem correctly. The teacher plans to take more samples like this.

Step-by-step explanation: Khan Academy Explanation

8 0

3 years ago

Fill in the table of values for y=2-x<br> X/ -3 0 5<br> Y

victus00 [196]

Answer:

I put in y = 2-x. I believe that was the equation you asked a table for. If it is another equation please tell me or just download or look up Desmos. Desmos helps create graphs and tables. I hope this helps. Have a great rest of your day!

8 0

3 years ago