Let x and y be the 2 parts of 15 ==> x + y=15 (given)
Reciprocal of x and y ==> 1/x +1/y ==> 1/x + 1/y = 3/10 (given)
Let's solve 1/x + 1/y = 3/10 . Common denominator = 10.x.y (reduce to same denominator)
==> (10y+10x)/10xy = 3xy/10xy ==> 10x+10y =3xy
But x+y = 15 , then 10x+10y =150 ==> 150=3xy and xy = 50
Now we have the sum S of the 2 parts that is S = 15 and
their Product = xy =50
Let's use the quadratic equation for S and P==> X² -SX +P =0
Or X² - 15X + 50=0, Solve for X & you will find:
The 1st part of 15 is 10 & the 2nd part is 5
Answer:
x = -4
Step-by-step explanation:
f(x) = x² - 16
This is the difference of squares
which factors as
f(x) = (x - 4)(x + 4)
Therefor the negative zero is
x = -4
Here's link to the answer:
tinyurl.com/wpazsebu
Answer:
x ≤ 6 and x ≥ 2
Step-by-step explanation:
For now, we will start with doing each problem at a time. Here is your equation:
2x - 4 ≤ 8
First, you want to get the variable by itself. So, you add 4 to both sides. It will look like this:
2x - 4 ≤ 8
+ 4 + 4
The four being added on the left side cancels out, and you add 4 to 8. Now, it should look like this:
2x ≤ 12
Next, you want the x by itself. So, you would divide both sides by 2.
2x ≤ 12
/2 /2
2 divided by 2 cancels out, and 12 divided by 2 equals 6. Now, you have a final answer of:
x ≤ 6
But, you now have to do the other one!
Here is what you start off with:
x + 5 ≥ 7
First, you want the variable side by itself. So, you subtract 5 from both sides.
x + 5 ≥ 7
- 5 -5
Now, you have this:
x ≥ 2
Because the variable is already by itself, you don't need to do any more division and this is you final answer. Now put both answers you got together which equals:
x ≤ 6 and x ≥ 2
Answer:
(x-3)(x^2-7) = x^3 -3x^2 -7x + 21
just change the sign of the root and put x in front of it, then multiply the factors all together
(x-3)(x-sqr7)(x+sqr7) roots come in conjugate pairs to eliminate irrational coefficients
(x-sqr7)(x+sqr7) = x^2-7. similar to (a-b)(a+b) = a^2-b^2
Step-by-step explanation:
