Why are equivalent equations important when solving a system using linear combination?

Determine the domain and range of the given function. the domain is all real numbers all real numbers greater than or equal to –2{x: x = –2, –1, 0, 1, 2}{y: y = –2, –1, 0, 1, 2}. the range is all real numbers all real numbers greater than or equal to –2{x: x = –2, –1, 0, 1, 2}{y: y = –2, –1, 0, 1, 2}.