[tex]x = \sqrt{676 + 2 + 4 + 6 + ... + 1350} [/tex]
[tex]x = \sqrt{676 + 2(1 + 2 + 3 + ... + 675)} [/tex]
[tex]x = \sqrt{676 + 2 \times \frac{675(675 + 1)}{2} } [/tex]
[tex]x = \sqrt{676 + 675 \times 676} [/tex]
[tex]x = \sqrt{676(1 + 675)} [/tex]
[tex]x = \sqrt{676 \times 676} [/tex]
[tex]x = \sqrt{ {676}^{2} } [/tex]
[tex]x = 676[/tex]
[tex] \sqrt{x} = \sqrt{676} = 26[/tex]