(a-9)(a+1)-(a+8)(a+3) при a=1/3

Question

(a-9)(a+1)-(a+8)(a+3) при a=1/3

Answer 1

( a - 9 )*( a + 1 ) - ( a + 8 )*( a + 3 ) = a2 + a - 9a - 9 - ( a2 + 3a + 8a + 24 ) = a2 - 8a - 9 - a2 - 11a - 24 = - 19a - 33 
a = 1/3 
- 19 * ( 1/3 ) - 33 = - ( 19/3 ) - 33 = - 6 ( 1/3 ) - 33 = - 39 ( 1/3 )