Question

iii) If n(n + 1) = 30, then n _________
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Answer 1

Answer:

n(n+1)=30

n^2 +n =30

2n^2 =30

n^2 =15

n =√15

Answer 2

Answer

n = 5

Step-by-step explanation:

n(n+1)=30,(multipication)

n^2+n=30,(Bringing 30 to other side)

n^2+n-30=0,(Breaking down middle term,a+b=n,ab= -30)

n^2+6n+(-5n)-30=0(factorization)

n(n+6)-5(n+6)=0

n+6=0,n-5=0

n=(5,-6)

Proof :

=5(5 + 1)         = -6(-6 + 1)

=5(6)              = -6(-5)

=30                = 30