Please help me again i only have a few questions left pleaseee i beg pre cal is so hard

What should be done to solve the equation? x+14=21 add 14 to both sides of the equation. subtract 14 from the left side of the equation. add 14 to the left side and subtract 14 from the right side of the equation. subtract 14 from both sides of the equation.

What two criteria are needed for triangles to be similar

How are algebraic expressions evaluated using substitution?