To solve an equation, use the properties of equality. What is the first step to solving 3.7x – 15.9 = 2.97? Subtract 15.9 from both sides because it is the inverse operation of addition. Add 15.9 to both sides because it is the inverse operation of subtraction. Divide 15.9 on both sides because it is the inverse operation of multiplication. Multiply 15.9 on both sides because it is the inverse operation of division.