You can use the trigonometric identity

.

The requirement that

eliminates -1/6 from being another solution.
Answer:
x=2 or x=−6
Step-by-step explanation:
Answer:
y = -2/3 + 18
Step-by-step explanation:
2x + 3y = 18 ----- here is the equation...
-2x - 2x ----- bring the 2x to the other side
3y = -2x + 18 ----- now you have to divide everything by 3 to get y by itself
y = -2/3 + 18 ----- Done!
Answer:
40
Step-by-step explanation:
to convert into radian measure, multiply by π/180
40 x π/10
9514 1404 393
Answer:
- 100 mL of 75% solution
- 150 mL of pure alcohol
Step-by-step explanation:
Let x represent the quantity (in mL) of pure alcohol needed for the mix. Then the amount of 75% needed is (250-x). The amount of alcohol in the mixture is ...
1.00x +0.75(250 -x) = 0.90(250)
0.25x +187.5 = 225 . . simplify
0.25x = 37.5 . . . . . . . . subtract 187.5
x = 150 . . . . . . . . . . . . . divide by 0.25
(250 -x) = 100 . . . . mL of 75% solution
You need 100 mL of the 75% solution and 150 mL of pure alcohol to obtain the desired mixture.