Question

a linear equation inn two different unknowns x and y is called a system of equation true or false

Answer 1

A system of equations describes a set of two (or more) equations in which there are different variables depending on how many equations there are.
For example, a system of equations would be
y = 2x + 3
2y = x + 1
I would say true.

Answer 2

This is false. ONE equation in two variables is not a system.