Answer:
5(2x-8)+15=-15
10x-40+15=-15
10x-25=-15
+25 +25 (add 25 to both sides)
____________
10x=10
divide by 10 on both sides
x=1
Answer:
3
Explanation:
4 is half of 8 on the right side, so that means X has to be half of 6, so it’s 3. Also, it couldn’t be 2 because it is too big, and it can’t be 4 because it isn’t the same length as the other 4, so it’s 3
Answer:
The correct matrices are:
Matrix:
7 1 5
1 5 7
5 7 1
all diagonal elements of A^2 are: 7^2 + 1^2 + 5^2
Matrix:
9 18 27
27 -9 18
18 27 9
all diagonal elements of A^2 are: 9^2 + 27*18 + 18*27 or (-9)^2
Matrix:
8 1 6
6 8 1
1 6 8
all diagonal elements of A^2 are: 8^2 + 6*1 + 1*6
Using the side of the square find the area:
Area = 30^2 = 900 square feet.
The rectangles area is the same, 900 square feet.
Let the width = X
The length would be 2X + 70
Area = length x width
X * 2x+ 70 = 900
This expands to 2x^2 * 70x = 900
Use the quadratic formula to solve for x:
-70 +/- sqrt(70^2-4*2(-900))/2*2
X = 10
Width = x = 10 feet
Length = 2x + 70 = 90 feet
