-2x + xy = 30.....when y = 8
-2x + 8x = 30
6x = 30
x = 30/6
x = 5 <==
Answer:
Lins house is 315 metres from school
Step-by-step explanation:
It's simple, just do 450-135.
Step-by-step explanation:
first of all, g(x) has only negative functional result values (y) except for 0.
and a square is always positive.
so, the only possible right answers are the ones that include a minus ("-") sign.
the graph shows us that g(x) goes through the points (1, -3) and (-1, -3).
so, which equation turns an x = 1 into an y = -3 ?
therefore, the right answer must be D.
g(x) = -3x²
it works for both points :
-3 = -3×1² = -3 correct
-3 = -3×(-1)² = -3×1 = -3 correct
Answer: cos(x)
Step-by-step explanation:
We have
sin ( x + y ) = sin(x)*cos(y) + cos(x)*sin(y) (1) and
cos ( x + y ) = cos(x)*cos(y) - sin(x)*sin(y) (2)
From eq. (1)
if x = y
sin ( x + x ) = sin(x)*cos(x) + cos(x)*sin(x) ⇒ sin(2x) = 2sin(x)cos(x)
From eq. 2
If x = y
cos ( x + x ) = cos(x)*cos(x) - sin(x)*sin(x) ⇒ cos²(x) - sin²(x)
cos (2x) = cos²(x) - sin²(x)
Hence:The expression:
cos(2x) cos(x) + sin(2x) sin(x) (3)
Subtition of sin(2x) and cos(2x) in eq. 3
[cos²(x)-sin²(x)]*cos(x) + [(2sen(x)cos(x)]*sin(x)
and operating
cos³(x) - sin²(x)cos(x) + 2sin²(x)cos(x) = cos³(x) + sin²(x)cos(x)
cos (x) [ cos²(x) + sin²(x) ] = cos(x)
since cos²(x) + sin²(x) = 1
X2-64=0
x2=64
x=8 because when multiplied by itself, and plugged back in, it works
