Answer:
Step-by-step explanation:
1) x² + 3x + 1 = 0
a = 1 b = 3 c = 1
=> Δ = b² - 4ac = 9 - 4.1.1 = 5 > 0
so the quadratic equation have 2 solutions
=> x =
or x =
2) x² + 4x - 8 = 0
a = 1 b' = 2 c = -8
Δ' = b'² - ac = 4 - 1.(-8) = 12 > 0
so the quadratic equation have 2 solutions
=> x =
or x =
3) x² - 5x -12 = 0
a = 1 b = -5 c = -12
Δ = b² - 4ac = 25 - 4.1.(-12) = 25 + 48 = 73 > 0
so the quadratic equation have 2 solutions
=> x =
or x =
144 the circumference is 360 because it’s a circle, 360/5=72 72(2)=144
I think it's 1/2 × length