m∡A = 70º
1) Considering that the Sum of the interior angles within a triangle is always 180º
2) We can write the following, and solve for x
x+80 + x +80 +40 = 180
2x +160 +40 = 180
2x + 200 = 180
2x =180-200
2x= -20
x=-10
3) So since angle A = x +80, we can plug it into that the value of x
m∡A = x +80º
m∡A=-10+80
m∡A = 70º
The expression can be simplified as:
k^3(k7/5)^-5
= k^(3+-5) * (7/5)^-5
(Collecting the powers of k at one side and the constants at other side)
= k^-2 * (5/7)^5
(Solving thr integer powers)
= k^-2 * (3125/16807)
4 / 9 = 0.44444444..........
4/9 = 44.44444444444444...%