Answer:
Step-by-step explanation:13.82, 14.47, 20.10
Y-2x=-3.5
x-2y=-14
then multiply the first term by 2
2y-4x=-7
x-2y=-14
then sum them
-3x=-21
x=-7
y=3.5
Answer:
The slope would also be -4.
Step-by-step explanation:
This is because parallel lines have the exact same slope. Since these two lines are parallel and the first has a slope of -4, the second must as well.
Answer:
11700 mm²
Step-by-step explanation:
A rectangle is a quadrilateral with two equal, opposite and parallel sides. Each of the angles in a rectangle is 90°.
The horizontal distance of the rectangle = r + r + r + r = 4r
The vertical distance = r + h + r = 2r + h
Where h is the distance between the midpoint of the 2 up circles and the midpoint of the down circle.
Using Pythagoras:
(2r)² = h² + r²
h² + r² = 4r²
h² = 3r²
h = √3r²
h = r√3
Vertical distance = 2r + h = 2r + r√3
Area of rectangle = vertical distance * horizontal distance
Area = 4r * (2r + r√3) = 8r² + 4r²√3 = 4r²(2 + √3)
Substituting:
Area = 4r²(2 + √3) = 4(28²)(2 + √3) = 11703.711 mm²
Area = 11700 mm² to 3 s.f
Answer:
90 hardcover books
Step-by-step explanation:
We can solve this by setting up a couple of equations.
Let's allow x to represent the number of paperbacks Tim owns, and allow y to represent the number of hardcover books he owns.
Using the information in the question, we can write the equations:
1)x = 4y-3
2) x+y=447
Let's rearrange equation 1 so that it is in standard form:
x-4y=-3
And then let's multiply equation 2 by 4 so that we can cancel out y when we solve the system of equations:
4(x+y=447)
4x+4y=1,788
Then we can add the two equations and solve for x:
1) x-4y=-3
+ 2)4x+4y=1,788
------------------------------------
5x=1,785
x=357
So now we now the number of paperback books Tim has is 357. Let's plug this into one of the original equations to solve for the number of hardcover books (y):
357+y=447
y=90
And now we know that Tim owns 90 hardcover books.
