Find the partial sum of the first 100 terms of the series 4,8,12,16 .

Hello : 
16-12=12-8=8-4=4  ...(common diff by arithmetic sequence)
a1= 4
an = a1+(n-1)r    .. r= 4
a100 = a1 +(100-1)×4 =4+99×4 =  5×99 = 495
the partial sum of the first 100 terms is : S100
S100 = 100/2(4+495) =24950

Repost your question with the two rates

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!