62 triangle a and 59 triangle b
Let's build the equation counting how many x's and 1's are there on each side.
On the left hand side we have 5x's and 8 1's, for a total of 
On the left hand side we have 3x's and 10 1's, for a total of 
So, the equation we want to solve is

Subtract 3x from both sides:

Subtract 8 from both sides:

Divide both sides by 2:

Answer:
x=5
Step-by-step explanation:
20(20-x) = 300
Divide each side by 20
20/20(20-x) = 300/20
20-x = 15
Subtract 20 from each side
20-x-20 = 15-20
-x = -5
Multiply each side by -1
x = 5
To add or subtract two complex numbers, the real part is added or subtracted from real part and the complex part is added to or subtracted from complex part as shown below:
(11 - 7i) - (16 - 11i)
= 11 - 7i - 16 + 11i
= -5 + 4i
So, the answer to this question is option B