A new operation is defined by "$" and "&": for any rational number, a $B = a, a & B = B, for example, 3 $2 = 3, 4 & 6 = 6 Define a new operation with "$" and "&": for any rational number, a $B = a, a & B = B, for example, 3 $2 = 3, 4 & 6 = 6, then what is the value of (2007 $2008) $(2006 $2005),

A new operation is defined by "$" and "&": for any rational number, a $B = a, a & B = B, for example, 3 $2 = 3, 4 & 6 = 6 Define a new operation with "$" and "&": for any rational number, a $B = a, a & B = B, for example, 3 $2 = 3, 4 & 6 = 6, then what is the value of (2007 $2008) $(2006 $2005),

2007$2008=2007
2006$2005=2006
(2007$2008)$(2006$2005)=2007$2006=2007
However, ask me, the symbol "&" is Is it useful Or is the question wrong?

For rational numbers x and y, a new operation is defined: X * y = MX + NY + 5, where m and N are constants. It is known that: 1 * 2 = 9, (- 3) * 3 = 2, find the value of M, N and 3 * 8

1*2=m+2n+5=9(1)
(-3)*3=-3m+3n+5=2(2)
(2) + (1) × 3
3n+6n+5+15=2+27;
9n=9;
n=1;
m=2;
∴3*8=3×2+8×1+5=6+8+5=19；
If you don't understand this question, you can ask,

In this paper, we define two new operations: for any rational number a and B, a {B = a + B / 2, try to calculate (1} 9)} (9} 5)

（1★9）★（9★5）
= (1 + 9/2)★(9 + 5/2)
= 11/2 ★ 23/2
= 11/2 + 23/4
= 45/4