Processing Math: Done

From Förberedande kurs i matematik 1

We multiply the top and bottom of the fraction by the conjugate of the denominator, 7+5 , and see what it leads to,

7−557−75=7−557−757+57+5=(7)2−(5)2(57−75)(7+5)=7−5577+557−757−755=25(7)2+557−757−7(5)2=257+557−757−75=2557−757=2(5−7)57=2−257=−35.