‌4(−15−8+α−2)+9(−5+12+2α−13)=0 ‌−100+4α−54+18α=0 ‌⇒α=7 ‌‌ Let ‌P≡(3λ−5,λ−4,−2λ+7) Direction ratio of PQ (3λ−1,λ−1,−2λ+5) But PQ‌⟂‌ℓ1 ‌⇒3(3λ−1)+1⋅(λ−1)−2(−2λ+5)=0 ‌⇒λ=1 ‌P(−2,−3,5)⇒|a|+|b|+|c|=10