Hello!!!

Hope you are doing great!!!

Consider refraction of light from infinity at first surface,

μ 2/v - μ 1/u = μ 2- μ 1/R

1.5/v1 - 1.75/-∞   = 1.5-1.75/-R

Consider refraction of this image from second surface

1.75/v2 - 1.5/v1 = 1.75-1.5/R

v2=3.5R

The image of light coming from infinity.

It is converging since focal length is positive.

Hope it helps!!!