Quadratic eqns-sum and product of roots

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.
JiaGengMaths
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Quadratic eqns-sum and product of roots

Postby JiaGengMaths » Thu Apr 19, 2012 8:33 am

The equation 2x^2+px+24=0(where p<0), has roots A and B where A-B=4. Evaluate A and B and hence, or otherwise, find the value of p.

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maggiemagnet
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Re: Quadratic eqns-sum and product of roots

Postby maggiemagnet » Fri Apr 20, 2012 1:27 pm

JiaGengMaths wrote:The equation 2x^2+px+24=0(where p<0), has roots A and B where A-B=4. Evaluate A and B and hence, or otherwise, find the value of p.

Divide through by 2. Then use the fact that, for roots A and B and equation x^2 + bx + c = 0, A + B = b and A*B = c.
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