Плмогите с заданием 31.3

1) a²-49=(a-7)(a+7)

2) 64-b²=(8+b)(8-b)

3) c²-2,25=(c+1,5)(c-1,5)

4) 2,89-d²=(1,7+d)(1,7-d)

5) $\frac{64}{81} -x^{2} = (\frac{8}{9} +x)(\frac{8}{9} -x)$

6) $\frac{100}{121} - y^{2} =(\frac{10}{11} +y)(\frac{10}{11} -y)$

7) $z^{2} -\frac{169}{196} =(z+\frac{13}{14} )(z-\frac{13}{14})$

8) $z^{2} -\frac{400}{441} =(z+\frac{20}{21} )(z-\frac{20}{21} )$

9) 25x²-36=(5x+6)(5x-6)

10) -16+49y²=49y²-16=(7y+4)(7y-4)

11) $0,64-\frac{1}{9}z^{2} =(0,8+\frac{1}{3}z)(0,8-\frac{1}{3}z)$

12) $\frac{4}{25}t^{2} -36=(\frac{2}{5}t+6) (\frac{2}{5}t-6)$