The mistake was on the second one, u use pempas, the multiplication comes first. The answer is 23
Distribute
to every term inside the parentheses.

Simplify with multiplication.

You can't simplify further by adding, so leave the answer as-is.
Answer:
S10 = 320
Step-by-step explanation:
The formula for calculating the sum of the nth term of an AP is expressed as
Sn = n/2(2a+(n-1)d))
Given
a = 4
d = 5
n = 10
S10 =10/2{2(5)+(10-1)5}
S10 =5{10+9(6)}
S10 =5{10+54}
S10 = 5(64)
S10 = 320
Hence the sum of the first ten terms of the sequence is 320