Hej!
a)
[tex]2-\frac{7-x}{3}=\frac{3x+2}{5}-1 \ \ |\cdot15\\\\30-5(7-x)=3(3x+2)-15\\\\30-35+5x=9x+6-15\\\\5x-9x=6-15-30+35\\\\-4x=-4 \ \ |:(-4)\\\\x=1[/tex]
b)
[tex](x-\frac{1}{2})^2-x^2-\frac{1}{4}=(2x-3)(2x+3)-(2x-3)^2\\\\x^2-x+\frac{1}{4}-x^2-\frac{1}{4}=4x^2-9-4x^2+12x-9\\\\-x=12x-18\\\\-x-12x=-18\\\\-13x=-18 \ \ |:(-13)\\\\x=\frac{18}{13}[/tex]
Pozdrawiam! - Julka
