I don't understand what you mean by 'mentally' but anyways, here is how to solve it.
(z−12)(z+12)
=(z+−12)(z+12)
=(z)(z)+(z)(12)+(−12)(z)+(−12)(12)
=z^2+12z−12z−144
=z^2−144
We are asked to find the distance (in radians) between 0 and pi, and sin 0 to 0.
The value of pi in degrees is 180 degrees. In radians, its value is 3.1415. So from 0 to pi, the distance is simple 3.1415 rad. Since sin 0 is equal to 0, then its distance from 0 is also 0. <span />
Answer: x=2.9, y=-1.6 and x=-1.7, y=6.7
PLEASE MARK ME AS BRAINLIEST
From the conditions given, the total number of the problems should be 29. This means that the sum of x and y should be 29. With this and the point-system, the best system of equation that is useful for this problem is,
x + y = 29
5x + 2y = 100
The answer is the second choice.