Robert is building a deck in his backyard. each piece of wood measures 42.5 inches. if he has 86 boards, how long are they altogether

You multiply 86 by 42.5 because each board is 42.5 and there are 86 boards.

Abit confused about what you mean, but i think you might be referring to slope intercept form: y = mx + bin that case b, or the y intercept is already given.(0,-1)find the slope by using the formulay2 - y1/x2 - x1the final slope will be 4/2, equivalent to 2.now your equation should look like thisy = 4/2x -1sorry if this didn’t you out!

Idon’t see a picture