x^2 + x whats the constant term

This expression (not equation, since an equation requires an equal sign with something on each side) is a quadratic (second degree polynomial).

The quadratic is in standard form:

ax^{2} + bx + c

Since you don't see a number written before x^{2} or x, their coefficients (a & b) are 1

Since you do not see anything written for the c (constant) term, it is 0

The constant term in the expression is 0