Question

for y=3×-2×^2+5×^3 show how to find the value for y when x=3.show your work

Answer 1

$\bf y=3x-2x^2+5x^3~\hspace{7em}\stackrel{\textit{let's say then x = 3}}{y=3(3)-2(3)^2+5(3)^3} \\\\\\ y=9-2(9)+5(27)\implies y=9-18+135\implies y=126$