Is 50 + 40 = x the equation?

Is 50 + 40 = x the equation?

Of course! An equation with unknowns is an equation!

Is 50 + 150 = x an equation?

An equation with unknowns is called an equation
Strictly speaking, it should not be

How to solve the problem? Thank you for your help!
It's the square of X

There is a rule: X1 + x2 = (- B / a) = 20, from which we can see that the median of the arithmetic is 10

Equation y_ 2) How to calculate = (x + 5) + 3

Two unknowns, one equation, have innumerable solutions
y=x+10
If you take any x, you have a y