## anonymous 4 years ago (7 minus 2 square root of 5)(5 plus 4 square root of 5) HELLPPPPPP

1. anonymous

35+18sqrt5-40 =-5+18sqrt5

2. campbell_st

$(7 - 2\sqrt{5})(5+4\sqrt{5})$ its binomial expansion lots of ways to do it |dw:1327559245628:dw| collect like terms

3. campbell_st

answer is $-5 + 18\sqrt{5}$

4. anonymous

The -5 Answer Was Correct. Thanks :D