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3 years ago

10 minutes to answer Write an expression equivalent to 4 - (-7) help

1 answer:

4 0

11 because -7 subtracted by 4 add kore to the 7 so think of it this way -7 is a bad guy and 4 is a bad guy to because its a subtraction so if both bad guys combine you get 11 because a negative with negative makes a positive so its 11

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ERROR ANALYSIS Describe and correct the error in ﬁnding the x-intercept.

EastWind [94]

The x-intercept is -6

Step-by-step explanation:

In order to find the x-intercept, we put y = 0 and to find the y-intercept we put x = 0

In the given method, x is put equal to zero instead of y as x-intercept had to be found.

Given equation is:

$-2x+3y=12$

$-2x + 3(0) = 12\\-2x +0 = 12\\-2x = 12$

Dividing both sides by -2

$\frac{-2x}{-2} = \frac{12}{-2}\\x = -6$

The x-intercept is -6

Keywords: Coordinate geometry, Intercepts

Learn more about intercepts at:

#LearnwithBrainly

3 0

3 years ago

6. This solid is a composite of a cube and square pyramid. The base of the solid is the base of the cube. Find the surface area

Sergio039 [100]

Answer:

960 ft^2

Step-by-step explanation:

There are 9 surfaces forming the solid.

5 of them are congruent squares and 4 of them are congruent triangles.

area of square = (side)^2

area of triangle = (base)(height)/2

total surface area = 5 * area of square + 4 * area of triangle

A = 5 * (12 ft)^2 + 4 * (12 ft * 10 ft)/2

A = 5 * 144 ft^2 + 4 * 60 ft^2

A = 720 ft^2 + 240 ft^2

A = 960 ft^2

3 0

2 years ago

Gravel is being dumped from a conveyor belt at a rate of 20 ft3/min, and its coarseness is such that it forms a pile in the shap

11Alexandr11 [23.1K]

Answer:

0.25 feet per minute

Step-by-step explanation:

Gravel is being dumped from a conveyor belt at a rate of 20 ft3/min. Since we are told that the shape formed is a cone, the rate of change of the volume of the cone.

$\dfrac{dV}{dt}=20$ ft^3/min$

$\text{Volume of a cone}=\dfrac{1}{3}\pi r^2 h$

Since base diameter = Height of the Cone

Radius of the Cone = h/2

Therefore,

$\text{Volume of the cone}=\dfrac{\pi h}{3} (\dfrac{h}{2}) ^2 \\V=\dfrac{\pi h^3}{12}$

$\text{Rate of Change of the Volume}, \dfrac{dV}{dt}=\dfrac{3\pi h^2}{12}\dfrac{dh}{dt}$

Therefore: $\dfrac{3\pi h^2}{12}\dfrac{dh}{dt}=20$

We want to determine how fast is the height of the pile is increasing when the pile is 10 feet high.

$h=10$ feet$\\\\\dfrac{3\pi *10^2}{12}\dfrac{dh}{dt}=20\\25\pi \dfrac{dh}{dt}=20\\ \dfrac{dh}{dt}= \dfrac{20}{25\pi}\\ \dfrac{dh}{dt}=0.25$ feet per minute (to two decimal places.)$