Помогите пожалуйста [latex] -\frac{4}{3} x^{2} +12=0[/latex] [latex] -\frac{4}{3} x^{2}+28=0

[latex]- \frac{4}{3}x^2+12=0\\\\ \frac{4}{3}x^2 =12\\\\x^2=12: \frac{4}{3}\\\\x^2= \frac{12*3}{4}\\\\x^2=9\\\\ \sqrt{x^2}= \sqrt{9}\\\\x=б3 [/latex] [latex]- \frac{4}{3}x^2+28=0\\\\\frac{4}{3}x^2=28\\\\x^2= 28:\frac{4}{3}\\\\x^2= \frac{28*3}{4}\\\\x^2=21\\\\ \sqrt{x^2}= \sqrt{21}\\\\x=б \sqrt{21} [/latex]