Δ=0⇒∣111475−2−5α∣=0
(7α+25)−(4α+10)+(−20+14)=0
3α+9=0⇒α=−3
Also Dz=0⇒∣1114751β5∣=0
1(35−5β)−(15)+1(4β−7)=0
β=13
JEE Main 2020 — Mathematics Algebra
If for some α and β in R , the intersection of the following three planes
x+4y−2z=1
x+7y−5z=β
x+5y+αz=5
is a line in R3 , then α+β is equal to:
Held on 9 Jan 2020 · Verified 6 Jul 2026.
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