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
X=18Plug in the numbers to get 72 + 108=180
Answer:
sorry sorry don't know this
Answer:
8.7°
Step-by-step explanation:
The above problem can be represented by a right angled triangle with height of 7 m, hypotenuse = AB.
The base of the triangle is gotten by finding the diagonal of the road. That is using Pythagoras theorem:
base² = 43² + 15²
base² = 2074
base = 45.54 m
Using trigonometric function to find angle A:
tan(A) = base / height
tan(A) = 45.54 / 7
tan(A) = 6.506
A = tan⁻¹ (6.506)
A = 81.3°
Angle of depression = 90° - A = 90 - 81.3
Angle of depression = = 8.7°
Answer: d = 3
41 or d is equivalent to 19.20937
Step-by-step explanation: not sure if this is correct but I tried