Question 1187623
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find the value of k and the other root of 4x^2 + kx + 15=0 if 5 is one of its roots
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<pre>
Let  " t "  be the other root.


Then, according to Vieta's theorem,  {{{15/4}}} = 5t,  which implies  t = {{{15/(5*4)}}} = {{{3/4}}}.


So, the other root is  {{{3/4}}}.


Next, according to Vieta's theorem  (again; this time another part of the Vieta's theorem)  {{{-k/4}}} = 5 + {{{3/4}}} = 5 {{{3/4}}} = {{{23/4}}}.


So,  k = -23.


<U>ANSWER</U>.  k = -23;  the other root is {{{3/4}}}.
</pre>

Solved.