\(9u^2-15uv+4v^2=\\\\9u^2-3uv-12uv+4v^2=\ \ \ \ \ \ \ |-15uv=-3uv-15uv\\\\3u(3u-v)-4v(3u-v)=\ \ \ \ \ \ \ |put\ something\ in\ front\ of\ bracket\\from\ first\ two\ numbers,\ also\ from\ the\ rest\ of\ numbers\ in\\ order\ to\ first\ and\ second\ bracket\ will\ be\ the\ same\ equation\\\\(3u-v)(3u-4v)\ \ \ \ \ \ \ |now\ we\ put\ from\ bracket\ this\ equation\)
