Question

X^2= 1

5^2 - 15=0


21=7x^2

16=9^2

Answer 1

a)

X^2= 1

x= \/1=> 1


b)

5^2 - 15=0
25 - 15 = 0
10 = 0


c)
21=7x^2
21/7 = x^2
x^2=3
x= \/3
x= 1,73



d)

16=9^2
16 = 81