[tex]\displaystyle 4x^2=6 \frac{1}{4} \\ 4x^2= \frac{6 \cdot 4+1}{4} \\ 4x^2= \frac{24+1}{4} \\ 4x^2= \frac{25}{4} \\ 4x^2 \cdot 4=25 \\ 16x^2=25 \Rightarrow x^2= \frac{25}{16} \Rightarrow x= \sqrt{ \frac{25}{16} } \Rightarrow x= \frac{ \sqrt{25} }{ \sqrt{16} } \Rightarrow x= \frac{5}{4} \\ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~x=- \sqrt{ \frac{25}{16} } \Rightarrow x=- \frac{ \sqrt{25} }{ \sqrt{16} } \Rightarrow x=- \frac{5}{4} [/tex]
