3) x² - 121 = 0
x² = 121
x' = +√121
x' = 11
_______________
x'' = - √121
x'' = -11
Solution ⇒ S{-11 ; 11 } or (x-11)(x+11)
4) 4x² + 144 = 0
4x² = -144
x² = -144 / 4
x² = -36
x = √-36
No solution ⇒ S = ∅
5) z²+10z+21 = 0
Δ = 10² - 4(1)(21)
Δ = 100 - 84
Δ = 16
x' = (-10+4) / 2 = -6/2 = -3
x'' = (-10-4) / 2 = -14/2 = -7
Solution ⇒ S{ -7 ; -3} or (x+3)(x+7)
The complete formula for circumference is:

Since we know the circumference of the circle is 314 inches, we can then solve for d, the diameter:

Using 3.14 for pi, we get:

Then solve for d:

And now we know the diameter of the circle is 100 inches.
Answer:
<h3>pls give the correct question the question is not correct</h3>
Answer:
2 hours
Step-by-step explanation:
Car travels from A to B at 60 miles/hour. Time of travel = 120/60 = 2 hour. Average speed of round trip = (120+120)/(2+3) = 48 miles per hour.
1/2n + 15 = 9 <== ur equation
1/2n = 9 - 15
1/2n = - 6
n = -6 * 2
n = - 12 <== ur solution