It is given that 2-5i/2 and 2+5i/2 are the root of the quadratic equation ax ^2-bx+29=0?

2017-01-16 10:16 pm
Solve the equation ax ^2-bx+29=4x.express your answer in the form of m+ni.

回答 (2)

2017-01-23 2:44 am
two forays:
find a and b obediently by sum and product of roots (-b/a, c/a)
then use quadratic formula to find the answer
-OR-
alter the formula ax ^2-bx+29 on LHS into (x-2+5i/2)(x-2-5i/2) , then use quadratic formula, same as above
2017-01-17 8:02 am
It is given that (2-5i)/2 and (2+5i)/2 are the root of the quadratic equation
ax ^2-bx+29=0,Solve the equation ax ^2-bx+29=4x.express your answer
in the form of m+ni.
Sol
(2-5i)+(2+5i)=b/a
4=b/a
b=4a
(2-5i)(2+5i)=29/a
29=29/a
a=1
b=4
ax^2-bx+29=4x
x^2-4x+29=4x
x^2-8x+29=0
x=[8+/-√(64-4*1*29)]/2=4+/-i√13


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