Y= 12 - x
27 + 3( 12 - x ) = 2x
Answer: X=60°
2sinXcosX = sinX
Divide through by 2sinX
cosX = 1/2
X = cos-1(1/2)
X= 60°
I prefer to use a midpoint formula that deals with both coordinates at once. For points A and B, their midpoint (M) is
... M = (A + B)/2
We can solve this for B by multiplying by 2 and subtracing A.
... 2M = A + B
... 2M - A = B
For your midpoint M(0, -10) and your endpoint A(-4, -5), the other endpoint will be
... B = 2(0, -10) - (-4, -5) = (2·0 -(-4), 2·(-10) -(-5))
... = (4, -15)
The simplest form is 2 with working out shown on photo
X + 2y - 6 = z..........x + 2y - z = 6
3y - 2z = 7
4 + 3x = 2y - 5z.....3x - 2y + 5z = -4
x + 2y - z = 6.....multiply by -3
3x - 2y + 5z = -4
---------------------
-3x - 6y + 3z = -18 (result of multiplying by -3)
3x - 2y + 5z = -4
--------------------add
-8y + 8z = - 22
-8y + 8z = -22
3y - 2z = 7 .....multiply by 4
----------------
-8y + 8z = -22
12y - 8z = 28 (result of multiplying by 4)
----------------add
4y = 6
y = 6/4 reduces to 3/2
-8y + 8z = -22
-8(3/2) + 8z = -22
-12 + 8z = -22
8z = -22 + 12
8z = -10
z = -10/8 reduces to -5/4
x + 2y - 6 = z
x + 2(3/2) - 6 = -5/4
x + 3 - 6 = -5/4
x - 3 = -5/4
x = -5/4 + 3
x = -5/4 + 12/4
x = 7/4
solution is (7/4, 3/2, -5/4).....x = 7/4, y = 3/2, and z = -5/4