Question

  (4a*2 -9) умножить на (1/(2a-3)  - 1/(2a+3))

Answer 1

$(4a^2-9)*(frac{1}{2a-3}-frac{1}{2a+3})=\\((2a)^2-3^2)*(frac{1}{2a-3}-frac{1}{2a+3})=\\(2a-3)(2a+3)*(frac{1}{2a-3}-frac{1}{2a+3})=\\(2a-3)(2a+3)*frac{1}{2a-3}-(2a-3)(2a+3)*frac{1}{2a+3}=\\(2a+3)-(2a-3)=2a+3-2a+3=6$