Find the product of (√2 + √5) (√7 - √5)

PLs help( a guy answered to this image (linked below) said I have to find that to find the answer) pls solve for me! THx :))))

Find the product of 2 5 7 5PLs help a guy answered to this image linked below said I have to find that to find the answer pls solve for me THx class=