(1)-49/y^2+16/x^2=
问题描述：
(1)-49/y^2+16/x^2=
(2)48-3t^2=
(3)x-14x+49=
(4)a-6a^2b^3+9a^3b^5=
(5)(a^2+b^2)-4a^2b^2=
答
（1）（7/Y+4/X)(-7/Y+4/X)
(2) 3(4-3T)(4+3T)
(3)(X-7)(X-7)
(4)A(3AB^2-1)(3AB^2-1)
(5)(A^2-B^2)(A^2-B^2)