Question 6
The number 3 has the following properties: it is one less than a square number, and five times of it is also one less than a square number.
$$3=4-1=2^2-1$$
$$5\times3=16-1=4^2-1$$
24 is another number with the same properties:
$$24=25-1=5^2-1$$
$$5\times24=121-1=11^2-1$$
What is the smallest number with the same properties that is greater than 25?
Paper instruction: Give a full solution.
$$3=4-1=2^2-1$$
$$5\times3=16-1=4^2-1$$
24 is another number with the same properties:
$$24=25-1=5^2-1$$
$$5\times24=121-1=11^2-1$$
What is the smallest number with the same properties that is greater than 25?
Paper instruction: Give a full solution.