Question 1151634
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2t+t+5=3
Subtract 3 on both sides
2t+t-2=0
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{{{2t+t+5=3}}}

{{{3t+5=3}}}

{{{3t=3-5=-2}}}

{{{t=-2/3}}}



The rest of your description is unrelated to the first part of it.


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?
{{{2t^2+t+5=3}}}

{{{2t^2+t+5-3=0}}}

{{{2t^2+t+2=0}}}
Does not appear factorable, so....


{{{t=(-1+- sqrt(1^2-4*2*2))/(2*2)}}}

{{{t=(-1+- sqrt(-15))/4}}}

{{{highlight_green(t=(-1+- i*sqrt(15))/4)}}}
Your AC and B do not seem to fit anything here.