Answer:
4
Step-by-step explanation:
Let's say B is the number of boys and T is the number of teachers.
T / (B + 18) = 2/21
B/18 = 4/3
Solve the second equation for B.
B = 24
Plug into the first equation to find T.
T / (24 + 18) = 2/21
T = 4
Answer: The correct answer is “this is a reflection across the x-axis”
Expand the left side:
(3x + 2) (5x + 1) = 15x² + 10x + 3x + 2 = 15x² + 13x + 2
Then a = 15 and b = 13, so a - b = 2.
5,6
55,56
65,66
555,556,565,566
655,656.665.666
Looks like there are 14 numbers that use only the digits 5 or 6 or both 5 or 6 that are under 1000.