
7 + 14 + 21 + ... + 105 =
= 7(1 + 2 + 3 + ... + 15)
= 7(15)(16)/2
= 840
Answer:
I don't know sorry
Step-by-step explanation:
ask tutor
Using cross multiplication

(x-4)(x+2)=0
x-4=0
x+2=0
Thus x=4,-2
The answer to you promovem would be 2,291.9 miles away