Question

7x^2-2=2

find the large root

Answer 1

7x^2=4
sqrt(7x^2) = sqrt(4)
7x = 2
x = 2/7

Answer 2

In first step, I took the -2 over to other side, so it became 4.

Answer 3

\[7x^2=4\]

\[x^2=\frac{4}{7}\]
\[x=\pm\frac{2}{\sqrt{7}}=\pm\frac{2\sqrt{7}}{7}\]

Answer 4

So we see that the large root is the positive one.

Answer 5

so its 4 ?

Answer 6

First lets move everything to one side, so that the right is 0:

7x^2 - 2 = 2

7x^2 - 2 -2 = 0

7x^2 - 4 = 0

Lets use the quadratic formula, since there is no bx, we know that b is 0:

\[x = \sqrt{112} / 14 = 4\sqrt{7}/14 = 2\sqrt{7}/ 7\]

so your answer is: \[2\sqrt{7}/7\]