262) 2) 2 1 3-2a 2 1 3-2a
______ - ______ - ______ =_______ - _______ -_______ =
4a+2 2a-1 1-4a^2 2(2a+1) -(1-2a) 1-4a^2
2-4a+4a+2-3+2a 1+2a 1
= ________________ = _____________ = ______
1-4a (1+2a)(1-2a) 1-2a
3) 1 4 a 1 4 a
__ - ________ + _______ = __ - ________ + __________ =
a a^2+4a 16-a^2 a a(a+4) (4+a)(4-a)
16-a^2-16+4a+a^2 4
= _________________ = _________
a(4+a)(4-a) 16-a^2
263) 2) m=12 n=-3
m-6n^2 2n m-6n^2 6n^2-3n 2n
________ + 3n - _____ = ________ + _______ - ______ =
2n-1 1-2n 2n-1 2n-1 -(2n-1)
m-6n^2+6n^2-3n+2n m-n 12+3 15
= __________________ = _______ = ______ = ____
2n-1 2n-1 -6-1 -7
4) m=2 n=-4
m^2-n 6m m^2-n m^2-7m 6m
_______ - m - ______ = _______ - _______ - ______ =
m-7 7-m m-7 m-7 -(m-7)
m^2-n-m^2+7m+6m 13m-n 26+4 28
= __________________ = _________ = _______ = ____
m-7 m-7 2-7 -5