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3 years ago

The problem below has been solved incorrectly. Identify and explain the error.

Mathematics

1 answer:

mylen [45]3 years ago

7 0

Answer:

If you look over the steps you can see that until 4x + x + 3 = 18, evertything is dandy. But the step after that 4x + x =21 seems a bit fishy.

Think about it they subtract 3 from both sides so the first side is correct

4x + x, but they added 3 to the other side:

$(4x+x+3) - 3 = 18 - 3\\4x+x = 15$

not

4x+x = 21

Then we solve for 4x + x = 15

$5x = 15\\x = \frac{15}{5} \\x = 3$

To solve for y we use :

y = x+3

y = 3+3 = 6

so (3,6) is the right answer

You might be interested in

Find the surface area of the cylinder to the nearest whole number. The figure is not drawn to

Anettt [7]

Answer:

correct option is 2187

Total surface area is 2,185.44 square inches.

lateral surface area is 640.56 square inches

Step-by-step explanation:

Given

radius of cylinder = 12 inches

height of cylinder = 17 inches

we will us value of pi as 3.14

surface area for cylinder consist of two part

1. lateral surface area which is gven by $2\pi rl$

where r is radius of cylinder and l is height of cylinder

Thus, lateral surface area for given cylinder is

$2\pi rl\\ =>2* 3.14*12*17\\=> 1281.12$

Thus, lateral surface area for given cylinder is 1281.12 square inches.

_________________________________

second part of surface area is area of two base (upper and lower) of cylinder.

area of base is given by area of circle $\pi r^2$

$area \ of \base = \pi r^2 = 3.14*12^2\\=>area \ of \base = 3.14*144 = 452.16$

This, area of base is for one base of cylinder

since there are 2 base

area of both base will be = 2* area of one base

= 2*452.16 = 904.32.

Thus, area of base is 904.32 sq. in.

_______________________________________

Total surface area of cylinder = area of two base+ lateral surface area of cylinder = 1281.12 square inches + 904.32 square inches

= 2,185.44 square inches.

Thus, total surface area is 2,185.44 square inches.

lateral surface area is 640.56 square inches

but option which is closest to calculated value is 2187.

Thus, correct option is 2187

___________________________________________

Note: this problem can be directly solved using formula

total surface area for cylinder = $2\pi r^2 + 2\pi rl$

5 0

3 years ago

Tlachihualtepeti is a pyramid in mexico. each side of the base measures 450 meters and had an original height of 66 meters. How

storchak [24]

Answer:

Basically, we are to determine the volume of that pyramid.

Right Regular Pyramid Volume = (Area of the Base * Height) ÷ 3

Volume = (202,500 * 66) ÷ 3

Volume = 4,455,000 cubic meters

By the way Wikipedia says that is the largest pyramid in the world.

Step-by-step explanation:

3 0

3 years ago

3.7 (negative 83 x minus 3) = 3.7 (7 x minus 30)

Leona [35]

Answer:

Step-by-step explanationnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn