Trig ratios can only be used on right triangles with acute measures.
If given an angle and there are adjacent and opposite sides, then use tan(opposite/adjacent)
If given an angle and there is an adjacent side and a hypotenuse, then use cosine(adjacent/hypotenuse)
If given an angle and there is an opposite and adjacent side, then use sin(opposite/hypotenuse)
A common mnemonic device used to memorize the trig rules is SOH-CAH-TOA
Answer:
C. When the equations -10x + 5y = -60 and -3x − 5y = -5 are added together, a third linear equation, -13x = -65, is formed, and it shares a common solution with the original equations.
Step-by-step explanation:
2x-y=12
-3x-5y=-5
multiply the first equation by -5
-10x +5y = -60
add the 2 equations together
-3x-5y=-5
-10x +5y = -60
-------------------------
-13x = -65
We use the addition property of equality which says adding the same thing to both sides, doesn't change the equation, so we will get the same answer as the original equation
To divide fractions be multiply by the resiprical
4 6 24
--- x ---- = ------
1 7 7
then simplify into a mixed number
3 3/7
Answer:
Amount invested at 8% is $9000 and amount invested at 18% is $21000.
Step-by-step explanation:
Let amount invested at 8% be x.
Let amount invested at 18% be y.
We get the 1st equation as:
........(1)
We get the second equation as:
=> 
or getting rid of the decimal by multiplying by 100 on both sides.
........(2)
Multiplying (1) by 8 and subtracting from (2) we get
So, y = 21000
And 
So, x = 9000
Therefore, amount invested at 8% is $9000 and amount invested at 18% is $21000.
