Answer:
2/5 ±i4/5sqrt(6)= t
Step-by-step explanation:
20= 4t -5t^2
Rewriting
20 = -5t^2 +4t
Divide by -5
20 = -5t^2 +4t
20/-5 = -5/-5t^2 +4/-5t
-4 = t^2 -4/5 t
Complete the square
Take the coefficient of t
-4/5
Divide by 2
-4/10 = -2/5
Square it
(-2/5)^2 = 4/25
Add to each side
-4 +4/25 = t^2 -4/5 t + 4/25
-100/25+4/25 = ( t-2/5)^2
-96/25 = ( t-2/5)^2
Take the square root of each side
sqrt(-96/25) = sqrt(( t-2/5)^2)
±isqrt(96/25)=( t-2/5)
±i4/5sqrt(6)=( t-2/5)
Add 2/5 to each side
2/5 ±i4/5sqrt(6)= t
