A.) $15 would seem like it would be right
T = 40000 + 40000(1.03) + 40000(1.03)^2 + ... + 40000(1.03)^15
Multiply the above equation by 1.03 giving
1.03(T) = 40000(1.03) + 40000(1.03)^2 + 40000(1.03)^3 + ... + 40000(1.03)^15 + 40000(1.03)^16
Now subtract the first equation from the second to give
0.03T = 40000(1.03)^16 - 40000
0.03T = 40000(1.03^16 - 1)
0.03T = 24188.26
T = 24188.26 / 0.03 = $806275.25
Two angles are supplementary when they <span>add up to 180 degrees.
x = angle
19x-60 = </span><span>supplement angle
x + 19x - 60 = 180
20x = 180 + 60
20x = 240
x = 240/20
x = 12</span>° ← answer
I believe you haven't included the system of equations for us to solve.
However, I will tell you that you need to solve for one variable in an equation and substitute that into the other equation.
For example:
x = yz; z = x/y
a = zb; a = (x/y)b
Hope this helps!