Which algebraic expression is a trinomial? x3 + x2 – startroot x endroot 2x3 – x2 4x3 + x2 – startfraction 1 over x endfraction x6 – x + startroot 6 endroot

1. 2. ∠b and ∠y are right angles. 3.? 4.? which two statements are missing in steps 3 and 4? ∠x ≅ ∠c △abc ~ △zyx by the sas similarity theorem. ∠b ≅ ∠y △abc ~ △zyx by the sas similarity theorem. = 2 △abc ~ △zyx by the sss similarity theorem. = 2 △abc ~ △zyx by the sss similarity theorem.