Help me out plz

Which value of m will create a system of parallel lines with no solution? y= mx - 6 8x - 4y = 12

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.

Find the x-intercepts for the parabola defined by this equation: y=-3x^2-6x+9