1、 It is proved that when a and B take any real number, the value of square of polynomial a + square of polynomial b-2a + 8b + 18 is always positive 2、 It is proved that for any real number x, y, the square of polynomial 2x-6xy + 9y-4x + 5 is always positive There are two questions,

1、 It is proved that when a and B take any real number, the value of square of polynomial a + square of polynomial b-2a + 8b + 18 is always positive 2、 It is proved that for any real number x, y, the square of polynomial 2x-6xy + 9y-4x + 5 is always positive There are two questions,

(1)
Prove: the square of a + the square of B - 2A + 8b + 18
=（a²-2a+1）+（b²+8b+16）+1
=（a-1）²+（b+4）²+1
Because (A-1) & sup2; ≥ 0, (B + 4) & sup2; ≥ 0
So: the original formula ≥ 1
So: the value is always positive
(2) The square of 2x - 6xy + 9y - 4x + 5
=（x²-4x+4）+（x²-6xy+9y²）+1
=（x-2）²+（x-3y）²+1
Because: (X-2) & sup2; ≥ 0, (x-3y) & sup2; ≥ 0
So the value of the original formula is ≥ 1
So: the value is always positive