Example: X=(–1,1)+"t"(2,3), t∈R is a line in vector form. Here: "a"=2, "a"=3, "x"=–1 and "x"=1. The line goes through the points ("x","y")=(–1,1) and ("x"+"a","y"+"a")=(1,4). The corresponding parametric form of this line is: "x"("t")= –1+2"t", "y"("t")=1+3"t". The unique slope-intercept form of this line is: "y"("x")=1.5"x"+2.5   (solve the first equation for "t" and substitute this result into the second equation).