With amounts measured in gallons, let
x = amount of 65% antifreeze
y = amount of 90% antifreeze
1 gal of the 65% brand contains 0.65 gal of pure antifreeze; x gal would contain 0.65x gal. Similarly, y gal of the 90% brand contains 0.90y gal of pure antifreeze.
To obtain 120 gal of 80% antifreeze solution (which contains 0.80•120 = 96 gal of pure antifreeze), we must have
x + y = 120 … … … … … [total volume of antifreeze solution]
0.65x + 0.90y = 96 … [total volume of pure antifreeze]
Solve the first equation for y :
y = 120 - x
Substitute this into the second equation and solve for x :
0.65x + 0.90 (120 - x) = 96
0.65x + 108 - 0.90x = 96
0.25x = 12
x = 48
Solve for y :
y = 120 - 48
y = 72
If a line <span>parallel </span>to one side of a <span>triangle </span>intersects the other two sides of the triangle, then the line divides these two sides proportionally.
Answer:
x = 15
Step-by-step explanation:
Sides opposite congruent angles are congruent:
x + 10 = 2x - 5
15 = x . . . . . . . . . add 5-x
The value of x is 15.
_____
I suppose you could show the intermediate step:
x +10 +(5 -x) = 2x -5 +(5 -x)
15 = x . . . . . simplified
Answer:
sin(-a)= -15 /17
Step-by-step explanation:
Alright, lets remember that sin(x) is odd function, which means that
wherever you watch an expression like this: sin(-a), you can use the odd functions property, and turn it like the following
sin(-a)= - sin(a)
Now, other thing to remember: 
So, we can obtain any value for sin(x) function starting from the opposite function, cos(x), using the following:
So, if cos(a)= - 8 / 17, using the above equation we obtain the value for sin(a)
Using the odd function property, we get the following result
sin(-a)= - sin(a) = -15/17
