The complex numbers z and w satisfy |z| = |w| = 1 and zw is not equal to -1. (a) Prove that \overline{z} = {1}/{z} and \overline{w} = {1}/{w}.
(b) Prove that {z + w}/{zw + 1} is a real number.
Can you please explain in detail? I'm trying to understand this. Thank you for your time.

Number of 50sen coins  =  13

Step-by-step explanation:

Let the number of 50sen coins be = x

Let the number of 20sen coins be  = y

Total coins  = 20

x + y = 20 (i)

Value of 50sen coins = 0.50*x = 0.50x

Value of 20sen coins = 0.20 *y = 0.20y

Total value = RM 6.10

0.5x + 0.2y = 6.10 (ii)

Multiply (i) by (-0.5) and then add the equations. So, x will be eliminated and we can find the value of y

(i) * (-0.5)      -0.5x - 0.5y = -10

(ii)                  0.5x  + 0.2y = 6.10 { add and now x will be eliminated}

                              - 0.3y = -3.90

Divide both sides by (-0.3)

y = -3.90/-0.3

y = 13

Plug in the value of y in equation (i)

x + 13 = 20

Subtract 13 from both sides

x = 20 -13

x = 7

Number of 50sen coins  =  13