`A = \sqrt{7-\sqrt{48}} + \sqrt{13+\sqrt{48}}`
`=\sqrt{4-4\sqrt{3}+3} + \sqrt{12+4\sqrt{3}+1}`
`=\sqrt{(2-\sqrt{3})^2} + \sqrt{(2\sqrt{3})^2+4\sqrt{3}+1}`
`=|2 - \sqrt{3}| + \sqrt{(2\sqrt{3}+1)^2}`
`=2 - \sqrt{3} + |2\sqrt{3}+1|`
`=2 - \sqrt{3} + 2\sqrt{3} + 1`
`=\sqrt{3} + 3`