(color(blue)(u)color(darkred)(+7v))(color(red)(u)color(green)(+7v))
You proceed to FOIL it:
Where you multiply the color(blue)"first term" with the color(red)"outer term" then you multiply the color(blue)"first term" with the color(green)"inner term":
(color(blue)(u))(color(red)(u))=u^2
(color(blue)(u))(color(green)(7v))=7uv
Now you multiply the color(darkred)"last term" with the color(red)"outer term" then you multiply the color(darkred)"last term" with the color(green)"inner term":
color(darkred)((7v))(color(red)(u))=7uv
color(darkred)((7v))(color(green)(7v))=49v^2
Now combine them:
u^2+7uv+7uv+49v^2
Simplify:
u^2+14uv+49v^2
