Find two numbers whose square increased by 15 equals 8 times the number.

Answer:5 and 3

So we let the number take the letter b, anc the expression of the question is:

b^2+15=8*b ... so

b^2+15=8b

Then we take the 8b to the other side of the equal sign so that it becomes ...

b^2+15-8b=0

Hence it becomes a quadatic equation following the principle ax^2+bx+c where x is the unknown ...

From there we work out to get two different numbers ... either b-5=0

b=5

Or b-3=0

b=3

So the two numbers are 5 and 3