a, x2 + 1 = 82
x2 = 82 - 1
x = \(\sqrt{81}\) = 9
b, x2 + \(\dfrac{7}{4}=\dfrac{23}{4}\)
x2 = \(\dfrac{23}{4}-\dfrac{7}{4}\)
x = \(\sqrt{4}=2\)
c, (2x + 3)2 = 25
(2x + 3) = \(\sqrt{25}\)
2x = 5 - 3
x = 2 : 2 = 1
d, (x + 5)3 = -64
(x + 5) = \(\sqrt[3]{-64}\)
x = (- 4) + (- 5) = -9