Prove that x2+6x+15 has no zero.
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Answered by
75
x²+6x+15
here, a=1, b=6 and c=15
now, determinant=b²-4ac=6²-4.1.15=36-60=-24<0
since the determinant is negative therefore it has no zeros.
here, a=1, b=6 and c=15
now, determinant=b²-4ac=6²-4.1.15=36-60=-24<0
since the determinant is negative therefore it has no zeros.
Answered by
54
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x²+6x+15=x²+2x+3x+15
x(x+2)
3(x+5)
As you see how the two equations in the parenthesis factoring don't match? A quadratic cannot have 3 zeroes, therefore it follows the trend of having the same thing in parenthesis...followed by a combination of what lies outside of them. In this case.... x+3.
x²+6x+15=x²+2x+3x+15
x(x+2)
3(x+5)
As you see how the two equations in the parenthesis factoring don't match? A quadratic cannot have 3 zeroes, therefore it follows the trend of having the same thing in parenthesis...followed by a combination of what lies outside of them. In this case.... x+3.
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