1. Prove or give a counterexample for the following statements:
a) Iff: A + B is an injective function and be B, then Is-1({b})= 1.

Empty box + box + empty box fill in the box is equal to 30 how

What set does not contain -3 the set of all real numbers the set of all integers the set of all whole numbers the set of all rational numbers

Aquadratic equation in standard from is written ax^2= bx+c, where a,b and c are real numbers and a is not zero?