6 - 34 + 96 - 384 +...
a 1 = 6 , a 2 = a 1 * ( - 4 ) , a 3 = a 2 * ( - 4 ), a 4 = a 3 * ( - 4)...
a 5 = - 384 * ( - 4 ) = 1,536
a 6 = 1536 * ( - 4 ) = - 6,144
a 7 = - 6,144 * ( - 4 ) = 24,576
This is a sum of a geometric sequence:
S 7 = 6 - 24 + 96 - 384 + 1,536 - 6,144 + 24,576 = 19,662
Another way to solve this:
S 7 = a 1 * ( r^n - 1) / ( r - 1 ) = 6 * (( - 4) ^7 - 1 )/ (- 4 - 1)=
= 6 * (-16,385) / (-5 ) = 19,662
Answer:
betty swam 21 jane swam 14
Step-by-step explanation:
Answer:
0.448 seconds
Step-by-step explanation:
d = -16t² -4t + 412
find t when d = 407
substituting d = 407 into the equation:
407 = -16t² -4t + 412 (subtract 407 from both sides)
-16t² -4t + 412 - 407 = 0
-16t² -4t + 5 = 0 (multiply both sides by -1)
16t² + 4t - 5 = 0
solving using your method of choice (i.e completing the square or using the quadratic equation), you will end up with
t = (-1/8) (1 + √21)= -0.70 seconds (not possible because time cannot be negative)
or
t = (-1/8) (1 -√21) = 0.448 seconds (answer)
If I'm understanding the question right then 10.5^2
Answer:
ans= 12-x=r1 coin...
Step-by-step explanation:
hope u can do..
