At equilibrium point, the demand equation is equal to the supply equation.
Given that the demand is Qd = 1500 - 250P, and supply is Qs = 850P, at equilibrium,
1500 - 250P = 850P
850P + 250P = 1500
1,100P = 1,500
P = $1.36
and the equilibruim Q is 1500 - 250(1.36) = 1,159
Therefore, the equilibruim P* is $1.36 and the equilibruim Q* is 1,159.