Question 1130468
Equation of the line passing through points (h,k) and (p,v):


The points (x,y) for which
These two slopes are equal -----


{{{(v-k)/(p-h)=(y-x)/(x-h)}}}


{{{y-k=((v-k)/(p-h))(x-h)}}}


{{{y=k=((v-k)/(p-h))x-((v-k)/(p-h))h}}}


{{{highlight(y=((v-k)/(p-h))x+k-((v-k)/(p-h))h)}}}


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Using your given points,
slope,  {{{(9-(-1))/(4-(-1))=2}}}


{{{(y-(-1))/(x-(-1))=2}}}, here some of the computations already done


{{{(y+1)/(x+1)=2}}}


{{{y+1=2(x+1)}}}, about the same as typical point-slope form


{{{y=2x+2-1}}}


{{{highlight(y=2x+1)}}}