Answer:
+4.24, -4.24
Step-by-step explanation:
We are given:
[tex]5u^2 - 90 = 0[/tex]
Simply move 90 to the right hand side and solve:
[tex]5u^2 = 90\\\\\\u^2 = \frac{90}{5} \\\\\\\u^2 = 18\\[/tex]
[tex]u = \sqrt{18}[/tex]
It is noteworthy that a square root has two solutions, the positive and the negative of a number i.e. ±x
This is because [tex](+x)^2 = x^2[/tex] and [tex](-x)^2 = -x * -x = x^2[/tex]
Hence:
[tex]u =[/tex] ±[tex]4.2426[/tex] ≅ ±4.24
The solutions of the equation are +4.24 and -4.24.
