what is an equation or step by step for this question, please. equation for the graph, where y depends on x.

Y=-x+4
Your slope is shown as (rise over run) -2/2 which is simplified to -1 so you just write -x, and your y intercept falls on 4 on the y axis. Y is dependent on x because whatever x variable you plug in will give you y. Ex: (2,?) we plug in 2 Y=-(2)+4, and get 2 so (2,2), which is confirmed by the graph.

3x+9+4x+x=8x+9that's the answer for your question.