You multiply the number outside the parenthesis with both of the numbers in the parenthesis separately.
The answer is 1690. First find
the amount of interest by a single investment by multiplying the investment
amount by the percent interest in decimal form. Then calculate the total by
adding up all the products of investment times interest. Matrices will allow to
multiply two things together and add the products up all at the same time. So
we need to find the investment matrix and interest matrix.
Investment matrix A (transposed) = (a1 a2 a3) = (13,000 12,000 4,000)
Interest Matrix B = (b1
b2 b3) = (0.05 0.06 0.08)
Amount of interest earned = a1b1 + a2b2 + a3b3
Amount of interest earned = (0.05) (13,000) + (0.06)
(12,000) + (0.08)(4,000)
Amount of interest earned = 1690
This answer would be D because an equilateral triangles angles are all the same
The surface area of a cube is the combined area of all of its faces. The faces of a cube are squares, so to find the area of one face, we simply need to multiply the side length, which is 20, by itself.
20 * 20 = 400
So one face has an area of 400 units squared. To find the surface area, we just need to add all of the individual areas together. Cubes have 6 faces, so we can just multiply 400 by the amount of faces there are.
400 * 6 = 2400
The net, when folded into a cube, has a surface area of 2,400 units squared.
Hope that helped! =)
