Let f and e represent the amount of 40% and 80% solutions used...
We are told the f+e=20 which means that f=20-e and we can say that:
(.4f+.8e)/20=.7, using f=20-e in this equation we see that:
.4(20-e)+.8e=14
8-.4e+.8e=14
8+.4e=14
.4e=6
e=15, and since f=20-e then
f=5
So 15 quarts of 80% solution is mixed with 5 quarts of 40% solution to produce a 20 quart mixture of 70% solution.
All these equations are in the form of ax^2 + bx + c = 0, where a, b, and c are some numbers. the discriminants of equations like this are equal to b^2 - 4ac. if the discriminant is negative, there are two imaginary solutions. if the discriminant is positive, there are two real solutions. if the discriminant is 0, there is one real solution.
<span>x^2 + 4x + 5 = 0
</span>b^2 - 4ac
4^2 - 4(1)(5)
16-20
-4, two imaginary solutions.
<span>x^2 - 4x - 5 = 0
</span>b^2 - 4ac
(-4)^2 - 4(1)(-5)
16 + 20
36, two real solutions.
<span>4x^2 + 20x + 25 = 0
</span>b^2 - 4ac
20^2 - 4(4)(25)
400 - 400
0, one real solution.
Answer:
Option B is correct
Step-by-step explanation:
Given:
f(x) = -20x^2 +14x +12 and
g(x) = 5x - 6
We need to find f/g and state its domain.
f/g = -20x^2 +14x +12/5x - 6
Taking -2 common from numerator:
f/g = -2(10x^2 - 7x - 6) / 5x -6
Factorize 10x^2 - 7x - 6= 10x^2 - 12x +5x -6
Putting in the above equation
f/g = -2(10x^2 - 12x +5x -6)/ 5x -6
f/g = -2(2x(5x-6) + 1 (5x-6)) / 5x-6
f/g = -2 ( (2x+1)(5x-6))/5x-6
cancelling 5x-6 from numerator and denominator
f/g = -2(2x+1)
f/g = -4x -2
The domain of the function is set of all values for which the function is defined and real.
So, our function g(x) = 5x -6 and domain will be all real numbers except x = 6/5 as denominator will be zero if x=5/6 and the function will be undefined.
So, Option B is correct.
Answer:
x - 9
Step-by-step explanation:
In this case, "simplify" directs that you 1) carry out the indicated multiplication and 2) combine like terms.
-3(x+3)+4x = -3x - 9 + 4x = x - 9
Answer:
(-5, 2)
Step-by-step explanation:
<u>plug x into the equation x - 5y = -15</u>
-5 - 5y = -15
add 5 to both sides: -5y = -10
divide by -5: y = 2
