Answer:
- 6 2/3 qt 80%
- 13 1/3 qt 20%
Step-by-step explanation:
It is often convenient to solve a mixture problem by letting a variable represent the quantity of the higher-concentration contributor to the mix.
__
We can let x represent the number of quarts of 80% solution needed. Then (20-x) is the number of quarts of 20% solution needed. The amount of salt in the final mix is ...
0.80x +0.20(20-x) = 0.40(20)
0.60x = 0.20(20) . . . . . . . . subtract 0.20(20) and simplify
x = 20/3 = 6 2/3 . . . . . . . . . divide by 0.60; quarts of 80% solution
(20 -x) = 13 1/3 . . . . . . . . . . amount of 20% solution needed
The teacher should mix 6 2/3 quarts of 80% solution with 13 1/3 quarts of 20% solution.
Rewriting the equation as a quadratic equation equal to zero:
x^2 - x - 30 = 0
We need two numbers whose sum is -1 and whose product is -30. In this case, it would have to be 5 and -6. Therefore we can also write our equation in the factored form
(x + 5)(x - 6) = 0
Now we have a product of two expressions that is equal to zero, which means any x value that makes either (x + 5) or (x - 6) zero will make their product zero.
x + 5 = 0 => x = -5
x - 6 = 0 => x = 6
Therefore, our solutions are x = -5 and x = 6.
Answer:
4
Step-by-step explanation:
.05x80=4
Step-by-step explanation:
the line passes through (6, 2) and (10, -1),
the slope =
(-1-2)/(10-6) = -3/4
the equation :
y-2 = -3/4(x -6)
Answer:
The answer is A.
Step-by-step explanation:
Lets call f(x)=y, so y= 4*(3*x-5), we want to find 'x', using 'y' as a the variable.
Now lets change the name of 'y' to 'x', and 'x' to f^-1(x).
f-1(x) = (x+20)/12
