Which number is a constant in the algebraic expression - x^2-6y+13x+7

A constant is defined as a number without a variable attacted to it. SO in your problem, the answer would be 7

Let's take a close look at x^2-6y+13x+7. Add the coefficient '1' in front of the first term: 1 x^2-6y+13x+7.

The numerals {1, - 6} are called "coefficients."

The final numeral, 7, stands alone. This is the "constant."