Which set or sets does the number 15 belong to

The correct answers are:

Real; rational; integer; whole; natural

Explanation:

Real numbers cover most of the numbers we work with; they contain everything except complex (imaginary) numbers.

Rational numbers are any numbers that can be written as a fraction. 15 can be written as 15/1, which is a fraction, so it is a rational number.

Integers include positive and negative numbers, but no decimals or fractions. 15 is a positive number with no decimal, so it is an integer.

Whole numbers are positive numbers from 0 up, with no fractions or decimals. 15 is a positive number with no decimal, so it is a whole number.

Natural (counting) numbers are positive numbers from 1 up, with no fractions or decimals. 15 is a positive number with no decimal, so it is a natural number.

answer:   x = 3 + √11     and     x = 3 - √11

step-by-step explanation:

x² - 6x + 9 = 11

(x - 3)² = 11

x - 3 = ±√11

    x = 3 ± √11

x = 3 + √11     and     x = 3 - √11