State the order of the given ordinary differential equation.
(1 − x)y'' − 7xy' + 5y = cos x

determine whether the equation is linear or nonlinear by matching it with (6) in section 1.1.

2nd Order because it contains a 2nd derivative ,y''

Linear because the y term is linear, in other words the y has no exponent, nor is it inside of a log or trig function.
ex:
ln(y) or sin(y) or e^y