(2sqrt6 + 3sqrt3)(sqrt6-5sqrt3)
FOIL...
2*6-10sqrt18+3sqrt18-15*3
12-7sqrt18-45
but sqrt 18=3sqrt2
-33+21sqrt2
check my work
¡Ì means sqrt.
Simplify (2¡Ì6+3¡Ì3)(¡Ì6-5¡Ì3)
I got 15¡Ì2 -45.
2 answers
how does sqrt 18=3sqrt2?