Answer:
x = - 3, y = - 1
Step-by-step explanation:
y = 7x + 20 -----> equation 1
4x - y = - 11
4x - ( 7x + 20 ) = - 11
4x - 7x - 20 = - 11
- 3x = - 11 + 20
- 3x = 9
x = 9 / - 3
x = - 3
Substitute x = - 3 in equation 1,
y = 7 ( - 3 ) + 20
= - 21 + 20
y = - 1
Hence,
x = - 3
y = - 1
To calculate this you need to imagine triangle which points are:
boat
Top of lighthouse
Bottom of lighthouse
That triangle has 90 degrees angle at bottom of lighthouse. That means that we can use trigonometry to determine length between boat and bottom of lighthouse
tan(25) = 89/x
x = 89/tan(25)
x = 190.86
after rounding, the answer is D, 191 feet
From Left side:
NOTE: sin²θ + cos²θ = 1
Left side = Right side <em>so proof is complete</em>
I think it is .8 i could be wrong i’m not sure
