Question

x2-9=0
x2-5=20
X2=49
X2+4=68​

Answer 1

X2 -9 = 0

x2 = 9

X = + - raiz 9

x = + 3 e -3

x² -5 = 20

x² -5 -20= 0

x²-25=0

x²= 25

x = raiz quadrada de 25

x = 5

x² = 49

x = + ou - √49

x = + ou - 7

pois 7 x 7 = 49

X2+4=68​

x2=68-4

x2= raiz quadrada de 64

x=  8