Let x represent the cost of the bench. We are told that the garden table costs $40 more than the bench. This means that the cost of the garden table is x + 40
Given that the combined cost of the garden table and the bench is $890, it means that
x + x + 40 = 890
2x + 40 = 890
2x = 890 - 40
2x = 850
x = 850/2
x = 425
The cost of the bench is $425