a = \frac12x\\b^2 = 4 => b = 2\\(\frac12x - 2)(\frac12x + 2) = 0\\\frac12x -2 =0; \frac12 x = 2; x= 4;\\\frac12x + 2=0; \frac12x = -2; x = -4\\x = 4; x = -4" alt="\frac14x^2 - 4 = 0\\a^2 - b^2 = (a-b)(a+b)\\a^2 = \frac14x^2 => a = \frac12x\\b^2 = 4 => b = 2\\(\frac12x - 2)(\frac12x + 2) = 0\\\frac12x -2 =0; \frac12 x = 2; x= 4;\\\frac12x + 2=0; \frac12x = -2; x = -4\\x = 4; x = -4" align="absmiddle" class="latex-formula">