2a-5
2a+5
-2a - 4 = -16.8 -2a = -12.8 a = -12.8/-2 a = 6.4
2
(a - 2b)(2a - b)
If you mean 3a*3a*2a then it is 18a^3 when simplified
2a-5
2a - a = a
2a+5
since a=1a, 3a-1a=2a
2a
-2a - 4 = -16.8 -2a = -12.8 a = -12.8/-2 a = 6.4
2
2a+6b
6a to the second power minus 8ab + 2a
2a + 11a - 5a = 8a
(a - 2b)(2a - b)