Can you help me solve for both questions, and show the step by step process please for the first one I got -1.375 but I don't think that's correct. Thank you for your time!

Combine like terms to make a simpler expression 3z+z

Consider the triangle. which shows the order of the angles from smallest to largest? angle a, angle b, angle c angle b, angle a, angle c angle b, angle c, angle a angle c, angle a, angle b

Which equation can be used to measure the density of water in a spherical water tank? let w represent the number of water particles within the region.