Using the variable x for the unknown number,
20 - (x + 4) = 6
is your answer!
Hope I helped :)
Answer:

Step-by-step explanation:
From the figure attached,
ΔABC is an equilateral triangle.
Therefore, by the property of the equilateral triangle,
Measure of each angle = 60°
By applying tangent rule in the right triangle ADC,





Explanation: As the least common multiple of two numbers is 60 , the two numbers are factors of 60 . Among {1,2,3,4,5,6,10,12,15,20,30,60} ,5 & 12 is the only two pair of numbers whose difference is 7 .
Answer: 5 & 12
Put the same variable on the same side first than solve
The answer would be B, because 12.80 times .15 is 1.92