Answer:
a>4 or a < 8
Explanation:
We can start with the inequality on the left
-a + 2(4+3a) > 28
expand using the distributive property
-a + 8 + 6a > 28
5a + 8 > 28
subtract 8 from both sides to isolate the variable and its coefficient
5a > 20
divide both sides by 5 to isolate a
a > 4
moving on to the inequality on the right
2a - (3a+4) > -12
treat the minus sign as a -1
2a + (-1)(3a+4) > - 12
expand
2a - 3a - 4 > - 12
-a - 4 > -12
add 4 to both sides to isolate a and its coefficient
-a > - 8
multiply both sides by -1 but change the sign because we are multiplying by a negative number
a < 8