Hello :
<span>5cosθ = 3cosθ - 1.
</span><span>5cosθ - 3cosθ = 1.
2cos</span>θ =1
cosθ =1/2
all solutions :
cosθ =cos<span>π<span>/3
</span></span>all solutions :
θ =π/3 +2kπ or θ = - π/3 +2kπ ....k in Z
Answer:
11
Step-by-step explanation:
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)
Please put more details in the question
The answer is (22) hope it helps have a great day
