-21x+28 is factored into:
-7(3x-4)
A1. 12 i.e option D
A2. 3n-7 i.e option A
A3. -6n+20 i.e option D
A4. -70 i.e option C
Step-by-step explanation:
aₙ = a₁ + (n - 1) × d
aₙ = the nᵗʰ term in the sequence
a₁ = the first term in the sequence
d = the common difference between terms
Using the above formula to solve the first part, we have :
For the second part, we have :
For the third part, we have :
For the fourth part, we have :
We use the formule: t=S/v. So:
+ t1= 160/100 = 8/5 hrs = 5760''
+ t2= 160/90 = 16/9 hrs = 6400''
=> t2-t1= 6400 - 5760 = 640'' = 10'40''
