How to complete the square when x has a number before it? (In really simple terms please!)
Eg, 2x^2 - 10x
Thanks.
2007-01-08 23:42:58 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
In your example, you must factor out the two from both terms, and put it in front of parentheses i.e. 2(x^2 - 5x )=____.Then when you complete the square, you must multiply that number by 2 before you add it to the right side of the equation.
Another example without fractions:
2x^2 + 20x + 1=0
2x^2 +20x = -1
2(x^2 + 10x+ )=-1
2(x^2 +10x + 25) = -1 + 50
x^2 + 10x + 25 = 49/2
(x+5)^2 = 49/2 then you procede as usual
2007-01-08 23:57:46 · answer #1 · answered by MollyMAM 6 · 0⤊ 0⤋
This is a quadratic equation. Firstly, make the equation equals to zero. Secondly, divide two X square by 2 to get one X square. Of course ten X will be changed into five X. Then take X square to add the half of the coefficent of X, after that square the whole result. After which subtract that result with the square of the half of the coefficent of X. I try to do it for you below:
2x^2-10x=0
2(x^2-5x)=0
2[(x-5/2)^2-(5/2)^2]=0
Thats all!
2007-01-09 08:06:58 · answer #2 · answered by runman2468 1 · 0⤊ 0⤋
In your case you could factor out a 2 and then complete the square as usual...
2(x² - 5x + 25/4)
2(x - 5/2)²
2007-01-09 07:56:02 · answer #3 · answered by Puzzling 7 · 1⤊ 0⤋
2(x^2 - 5x + 25/4) = 25/2
2(x - 5/2)² = 25/2
(x - 5/2)² = 25/4
x - 5/2 = +-(5/2)
x = 0
x = 5
2007-01-09 08:07:06 · answer #4 · answered by ? 6 · 0⤊ 0⤋
Just substute the value of the root Suppose root 2 is there its approx. value is 1.414s substute it.!!!!
2007-01-09 08:40:22 · answer #5 · answered by Haritha 2 · 0⤊ 0⤋