Help ASAP please both questions

Given the system of linear equations.

Karo-lina-s [1.5K]

Part A:

x + y = 9

4x + y = 6

To solve this system using substitution, begin by isolating either x or y in the first equation. I'll isolate x.

x + y = 9

x = 9 - y

Substitute this expression (9 - y) into the second equation for x and solve.

4x + y = 6

4(9 - y) + y = 6

36 - 4y + y = 6

36 - 3y = 6

-3y = -30

y = 10

To find x, substitute 10 for y into either of the original equations.

x + y = 9

x + 10 = 9

x = -1

Finally, check all work by substituting the x- and y-values into each original equation.

x + y = 9 --> -1 + 10 = 9 --> 9 = 9 --> True

4x + y = 6 --> 4(-1) + 10 = 6 --> -4 + 10 = 6 --> 6 = 6 --> True

The answer for Part A is x = -1 and y = 10; (-1, 10).

Part B:

For graphing, it's easier to get the equations into slope-intercept form. Slope-intercept form is y = mx + b, where m is the slope and b is the y-intercept. To get our equations into slope-intercept form, we must simply isolate y.

x + y = 9

y = 9 - x

y = -x + 9

4x + y = 6

y = 6 - 4x

y = -4x + 6

Now that we have our slope-intercept equations, we can easily graph them, since their slopes and y-intercepts are readily visible.

Let's start with the y-intercepts. They are (0, 9) and (0, 6). You can plot those points on the graph.

Now, the slopes. The slope of the first line is -1, this means it declines. To plot this, start where you plotted the y-intercept, count one unit down, and then one unit to the right, and plot that point. Continue doing that and connect the dots, and you will have plotted the first line. The slope of the second line is -4, so it also declines. For this line, count four units down, and then one to the right and plot that point. Likewise, continue this and connect the coordinates, and you will have your line. (See attachment for graph.)

The lines do indeed intersect at (-1, 10); our answer is verified by graphing.

5 0

3 years ago

How to calculate a probability

Lelu [443]

Probability is calculated by comparing the odds to a certain event occurring to the number of possible events.

P= $\frac{possibility-of-an-event-occuring}{number-of-total-outcomes}$

For example, take a six-sided dice number 1-6 on each side. The probability of rolling a 4 would be1 in 6 or 1/6. This is because of the six possible outcomes, rolling a 4 is only one of them.

P(4)=1/6

Now take the same dice. The probability of rolling an even number is 3/6. To see why, lets look at the total possible outcomes:

1
2
3
4
5
6

Of the 6 possibilities, 3 are even numbers.

P(even)=3/6 or 1/2

6 0

2 years ago

A company is constructing an open-top, square-based, rectangular metal tank that will have a volume of 49 cubic feet. What dime

yawa3891 [41]

Answer:

b = 4.6 ft

h = 2.3 ft

Step-by-step explanation:

The volume of the tank is given by:

$b^2*h=49$

Where 'b' is the length of the each side of the square base, and 'h' is the height of the tank.

The surface area can be written as:

$A=b^2+4bh\\A=b^2+4b*({\frac{49}{b^2}})\\A=b^2+\frac{196}{b}$

The value of b for which the derivate of the expression above is zero is the value that yields the minimum surface area:

$\frac{dA}{db} =0=2b-\frac{196}{b^2}\\2b^3=196\\b=4.61\ ft$

The value of h is then:

$h=\frac{49}{4.61^2}\\h=2.31\ ft$

Rounded to the nearest tenth, the dimensions are b = 4.6 ft and h = 2.3 ft.

7 0

3 years ago

Help me ASAP please!!!

tia_tia [17]

swimming pool is full

6 0

3 years ago

When looking at a problem how can you tell if it is a power of power rule or power of product rule

LiRa [457]

Power of power rule:

Zero-Exponent Rule: a0 = 1, this says that anything raised to the zero power is 1. Power Rule (Powers to Powers): (am)n = amn, this says that to raise a power to a power you need to multiply the exponents. ... Only move the negative exponents.

Power of product rule:

The exponent "product rule" tells us that, when multiplying two powers that have the same base, you can add the exponents. ... Adding the exponents is just a short cut! Power Rule. The "power rule" tells us that to raise a power to a power, just multiply the exponents.

8 0

3 years ago