How do you graph and solve and tell whether it is linear or not ?
y= -x^2+1

Graph by plugging in points like x=1, x=2, x=3, x=4 until you can see a pattern

linear equations are only when the highest power of x is 1
for example  y = x + 1  is linear

but since this contains a x^2 it is a quadratic, Not Linear

The answer is all about the number 4