40 times what equals 180

Nine more than four times a number is the same as one less than twice the number. find the number?

Consider a cube that has sides of length l. now consider putting the largest sphere you can inside this cube without any point on the sphere lying outside of the cube. the volume ratio -volume of the sphere/ volume of the cube is 1. 5.2 × 10−1 2. 3.8 × 10−1 3. 1.9 4. 2.5 × 10−1 5. 3.8

Which pair of expressions is equivalent? a 7(1–k)and7–k b 7(1–k)and1–7k c 7(1–k)and7–k d 7(1–k)and7–7k