Answer:
The solution of this system of equations is (3 , -8)
Step-by-step explanation:
The given system is
x + 2y = -13
12x + 5y = -4
We make x the subject of the first equation and put it into the second:
We put this expression for x into the second equation
12(-13-2y)+5y=-4
-156-24y+5y=-4
-24y+5y=-4+156
-19y=152
y=-8
We substitute y=-8 into x=-13-2y to get:
The solution of this system of equations is (3 , -8)
Answer: Choice A. sin(A) = cos(B)
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Explanation:
The rule is that sin(A) = cos(B) if and only if A+B = 90.
Note how
Since both result in the same fraction BC/AB, this helps us see why sin(A) = cos(B). Similarly, we can find that cos(A) = sin(B).
In the diagram below, the angles A and B are complementary, meaning they add to 90 degrees. So this trick only applies to right triangles.
The side lengths can be anything you want, as long as you're dealing with a right triangle.
