Urgent...
One of the roots of quadratic equation
2x2 + x – 300 = 0 is
(1) 16 (2) 18
(3) 15 (4) 12
tSankar:
12
Answers
Answered by
115
Option 4 is correct (12)
Given:
2x²+ x - 300 = 0
2x² - 24x +25x -300= 0
2x(x-12) +25(x-12)= 0
(2x+25) (x-12)= 0
2x+25=0, x-12=0
2x+25=0
2x= -25
x= -25/2
x-12=0
x=12
Hence, One of the roots of quadratic equation is 12
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Hope this will help you....
Given:
2x²+ x - 300 = 0
2x² - 24x +25x -300= 0
2x(x-12) +25(x-12)= 0
(2x+25) (x-12)= 0
2x+25=0, x-12=0
2x+25=0
2x= -25
x= -25/2
x-12=0
x=12
Hence, One of the roots of quadratic equation is 12
==================================================================
Hope this will help you....
Answered by
27
Given quadratic equation is:
2 x² + x – 300 = 0 .......... (1)
There are two ways to check which of the given values are the roots of quadratic equation.
One method is to factorize the given equation and calculate the value of "x" .
The other method is to simply put the values of "x" , given in options and check whether we get zero on both sides or not.
First put x = 16 in Eq. (1)
2 (16)² + 16 - 300 = 0`
512 + 16 - 300 = 0
228 ≠ 0
Now put x = 18 in Eq. (1)
2 (18)² + 18 - 300 = 0
648 + 18 - 300 = 0
366 ≠ 0
Now put x = 15 in Eq. (1)
2 (15)² + 15 - 300 = 0
450 + 15 - 300 = 0
165 ≠ 0
Now put x = 12 in Eq. (1)
2 (12)² + 12 - 300 = 0
288 + 12 - 300 = 0
288 - 288 = 0
0 = 0
Which clearly shows that "12" is the root of the given quadratic equation.
2 x² + x – 300 = 0 .......... (1)
There are two ways to check which of the given values are the roots of quadratic equation.
One method is to factorize the given equation and calculate the value of "x" .
The other method is to simply put the values of "x" , given in options and check whether we get zero on both sides or not.
First put x = 16 in Eq. (1)
2 (16)² + 16 - 300 = 0`
512 + 16 - 300 = 0
228 ≠ 0
Now put x = 18 in Eq. (1)
2 (18)² + 18 - 300 = 0
648 + 18 - 300 = 0
366 ≠ 0
Now put x = 15 in Eq. (1)
2 (15)² + 15 - 300 = 0
450 + 15 - 300 = 0
165 ≠ 0
Now put x = 12 in Eq. (1)
2 (12)² + 12 - 300 = 0
288 + 12 - 300 = 0
288 - 288 = 0
0 = 0
Which clearly shows that "12" is the root of the given quadratic equation.
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