Answer:
The solution is x = -2, y = -3
Step-by-step explanation:
Let's start with the equation 3x + y = -9
Substitute the y for 5x+7 seen in the second equation
Now you have 3x + (5x+7) = -9
Lets solve:
Let's add the x's
Now we have 8x + 7 = -9
Substracy seven from each side
Now we have 8x = -16
Now let's divide 8 on each side
Now we have x = -2
Now lets plug in -2 to the second equation
The second equation is y = 5x+7
When we plug in -2 we get y=5(-2)+7
We multiply
We now have y = -10+7
Add
y = -3
The solution is x = -2, y = -3
<span>the answer to this is (3,-2)</span>
Answer:
1/3(3.14)2^2(24)
Step-by-step explanation:
The volume of a cone is given by the formula;
1/3πr³
Considering the radius is 2 cm and the height is 24 cm (4 times the diameter).
Therefore;
Volume = 1/2(3.14)2²(24)
This can be used to calculate the volume.
Answer:
.
Step-by-step explanation:
Assume that the run of this rafter is level. Then the height of the ridge (the line with a question mark next to it in the diagram) should be perpendicular to the line marked with 
. The three labelled lines in this diagram will form a right triangle.
- The line marked as
will be the hypotenuse of this right triangle. - The line marked as
will be one of the triangle's legs. - The line representing the height of the ridge (the one with the question mark) will be the other leg of this right triangle.
Hence, the height of this ridge can be found with the Pythagorean Theorem. By the Pythagorean Theorem:
.
In this particular right triangle:
.
.
Therefore, the height of this ridge would be 
. (Note the unit.)
Answer:
20
Step-by-step explanation:
You have to fill in 6 slots _ _ _ _ _ _.
Since first digit must be 4, there is only 1 way to fill in the 1st slot.
with the 5 slots, we fill in the 6s first, 3 of them.
So we have 5 options and 3 items to fill, (5 choose 3).
Then 2 ways to fill 1 and 1 way to fill 5. (It doesn't matter if you pick 5 or 1 first).
So it becomes (5C3) * (2C1) *(1C1)
= 1 * 5!/(3!)(5-3)! * (2) * 1
= 20
