Hello :
cos²(θ) +sin²(<span>θ) = 1
(1/4)² +sin²(</span><span>θ) = 1
</span>sin²(θ) = 1 -1/16
sin²(θ) =15/16
sin(θ) = - √(15/16)=- √15/4 because : <span>sin θ < 0.
</span>tan (θ) =sin (θ)/ cos( θ) =(- √15/4)/(1/4) = - √15
129 is 249 degrees warmer than -120 because -120+120=0 and then you add 129 to 0 which is 129. that means you add 120 and 129 to get 249
-3x + 18 = 7x
3x + (-3x) + 18= 7x + 3x
18 = 10x
18 10x
— = —
10 10
1.8 = x