Question

the sum of three consecutive multiples of 7 is 63 find these multiples

Answer 1

Let the three multiples be 7x,7x+7and 7x+14
7x+7x+7+7x+14=63
21x+21=63
21x=63-21
x=42/21
x=2
so...
7x=14
7x+7=21
7x+14=28

Answer 2

consecutive number is x, x+7 ,x+14
x+x+7+x+14=63
3x+21=63
3x=63-21=42
x=42/3=14
x=14
x+7=14+7=21
x+14=14+14=28