Question 462262: 1. Rewrite y = x2 + 14x + 29 in general form.
2. Rewrite y = 3x2 - 24x + 10 in general form.
3. Solve for x: (x - 9)2 = 1
4. Solve for x: x2 + 24x + 90 = 0
5. Solve for x: 2x2 - 4x - 14 = 0
6. Create your own quadratic equation and demonstrate how it would be solved by graphing, factoring, the quadratic formula, and by completing the square.
the general solution using the quadratic equation is:
So lets solve ( notice , , and )
Plug in a=2, b=-4, and c=-14
Negate -4 to get 4
Square -4 to get 16 (note: remember when you square -4, you must square the negative as well. This is because .)
Multiply to get
Combine like terms in the radicand (everything under the square root)
Simplify the square root (note: If you need help with simplifying the square root, check out this solver)
Multiply 2 and 2 to get 4
So now the expression breaks down into two parts
or
Now break up the fraction
or
Simplify
or
So the solutions are:
or
6. Create your own quadratic equation and demonstrate how it would be solved by graphing, factoring, the quadratic formula, and by completing the square.
In order to factor , first we need to ask ourselves: What two numbers multiply to 2 and add to 3? Lets find out by listing all of the possible factors of 2
Factors:
1,2,
-1,-2,List the negative factors as well. This will allow us to find all possible combinations
These factors pair up to multiply to 2.
1*2=2
(-1)*(-2)=2
note: remember two negative numbers multiplied together make a positive number
Now which of these pairs add to 3? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 3
First Number
|
Second Number
|
Sum
1
|
2
|
|
1+2=3
-1
|
-2
|
|
-1+(-2)=-3
We can see from the table that 1 and 2 add to 3. So the two numbers that multiply to 2 and add to 3 are: 1 and 2
Now we substitute these numbers into a and b of the general equation of a product of linear factors which is:
substitute a=1 and b=2
So the equation becomes:
(x+1)(x+2)
Notice that if we foil (x+1)(x+2) we get the quadratic again