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Answer:
<u> BC = 10 and AD = 30</u>
Step-by-step explanation:
In figure-1 , AB = CD ,BK ⊥ AD, AK = 10, KD = 20.
Since, line AD is sum of AK and KD, then
AD = AK + KD
AD = 10 + 20
AD = 30
Since, BC ║AD and BK ⊥ AD then similarly we construct CL ⊥ AD
so, BC = KL and AK = LD
KL = AD - LD
KL = 20 - 10
KL = 10
Since, BC = KL then BC = 10
Hence, <u> BC = 10 and AD = 30</u>
You solve the equation : t^2 - 9t - 90 = 0 ;
Δ = ( - 9 )^2 - 4 * 1 * ( - 90 ) = 81 + 360 = 441 ;
t1 = ( 9 +

) / 2 = 30 / 2 = 15 ;
t2 = ( 9 -

) / 2 = -12 / 2 = - 6 ;
The numbers are 15 and - 6 ;