(a-3)(a+4)-(a+2)(a+5) если a= -1/6

Question

(a-3)(a+4)-(a+2)(a+5) если a= -1/6

Answer 1

(-1/6-3)(-1/6+4)-(-1/6+2)(-1/6+5)=
(-3 1/6)* 3 5/6 + 1 5/6* 4 5/6 =
- 19/6 * 23/6 + 11/6* 29/6=
-19*23/36 + 11*28/36=
- 437/36 + 308/36=
-129/36= - 3 21/36= -3 7/12