How do you solve 64x2-5 equals 11?

64x^(2) - 5 = 11

Equate to zero , by subtracting '11' from both sides.

Hence

64x^(2) - 16 = 0

Algebraically rearrange

(8x)^(2) - 4^(2) = 0

We now have two squared terms with a negative between them. This factors to :-

(8x - 4)(8x + 4) = 0 Note the different signs in each brackets.

Hence

8x - 4 = 0

8x = 4

x - 4/8

x = 1/2

&

8x + 4 = 0

8x = -4

x = -4/8

x = -1/2

So the two solutions are x = 1/2 & x = -1/2

NB Twosquared terms with a POSITIVE(+) between them , does NOT factor.