I get 433 divided by 8 .... 433/8
Answer:
x = 31/3
Step-by-step explanation:
4x+8+2x+20=90
4x+2x+8+20=90
4x+2x+8+20=90
6x+28=90
6x+28-28=90-28
6x=62
x = 31/3
Answer:
Step-by-step explanation:
Find the sum of the first 42 terms of the following series, to the nearest integer.
2,7,12
Solution
The sum is given by
SUM_n=n/2*(a_1+a_n)
a_n=a_1+(n-1)d
a_1=2, n=42, d=5
The 42nd term is therefore given by
a_42=2+(42-1)5=207
SUM_42=42/2*(2+207)=21*209=4389
The sum of the first 42 terms of the series, therefore, is 4389