Answer:
4b is simplified. There are no like terms to combine.
[tex] {b}^{2} [/tex]
is the only term with exponent of 2.
13b is the only term b, exponent of 1.
13 is the only number.
Step-by-step explanation:
For 4d, it is hard to see but I think it is
[tex]7a + 4 - 6 {a}^{2} - 2a[/tex]
Reorder terms from largest to smallest exponent.
[tex] - 6 {a}^{2} + 7a - 2a + 4[/tex]
[tex] - 6 {a}^{2} + (7 - 2)a + 4[/tex]
[tex] - 6 {a}^{2} + 5a + 4[/tex]
