1. (a -3)² -a(5a -6) =a² -6a + 9 -5a² +6a=9 -4a²=(3 -2a)(3 +2a) =(3 +2*1/2)(3 -2*1/2)= (3 +1)(3 -1) =4*2=8
2. (11/4 +11/5) *16 = (11*5 + 11*4) *16) /20 =(55+44)*4)/5 =396/5 =79.2
3. x^(-1)=1/x^1
(16/10²)² *(13 *10^4) = (256 * 13 *10^4) /10^4 =256 *13 =
3328