It requires a force of 530 N to stretch a certain linear spring 0.28 m. What is the constant for this spring?
force: F = 530 N
displacement: x = 0.28 m
Starting formula 

Algebra: divide both sides by x 

Algebra: x's cancel on right 

Algebra: switch left and right 

Plug in numbers with units 

Divide: 530/0.28 = 1892.857.... 

Final result with significant figures and unit 