Answer:
a decrease in equilibrium quantity
an indeterminate effect on equilibrium price.
Explanation:
An increase in the price of steel would raise the production cost of cars. as a result the supply curve would shift inwards or to the left. price would rise and quantity would fall.
A rise in the price of gasoline would increase the cost of fuelling one's car. As a result the demand for cars would fall. the demand curve would shift inward. Quantity and price would fall.
Taking these two effects together, there would be a decrease in equilibrium quantity but an indeterminate effect on equilibrium price.
Check the attached image for a diagram explaining the effects of these changes
