(Radical 15- radical 5) (radical 15 + radical 5) and radical (-20) squared /2
2 answers
Second ones answer is 10 what about 1st? 1? 0?
If I read the first one correctly ...
(√15 -√5)(√15 + √5)
= 15 + √5√15 - √5√15 - 5
= 10
If the second one is (√-20)^2 / 2
= -20/2
= -10
long way:
(√-20)^2 / 2
= (1/2) √-20 * √-20
= (1/2) i√20 * i√20
= (1/2) (20)(i^2) , but i^2 = -1
= (1/2)(20)(-1)
= -10
(√15 -√5)(√15 + √5)
= 15 + √5√15 - √5√15 - 5
= 10
If the second one is (√-20)^2 / 2
= -20/2
= -10
long way:
(√-20)^2 / 2
= (1/2) √-20 * √-20
= (1/2) i√20 * i√20
= (1/2) (20)(i^2) , but i^2 = -1
= (1/2)(20)(-1)
= -10
1 answer