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Question

3(1+4n)-2(5n-3)=25

Answer 1

3(1 + 4n) - 2(5n - 3) = 25

Recall : Distributive property a(b + c) = ab + ac and a(b - c) = ab - ac

3 + 12n - 10n + 6 = 25

9 + 2n = 25

2n = 16

n = 8.

Answer 2

3(1+4n)-2(5n-3)=25

Apply distributive property a ( b + c ) = ab + ac

3 + 3 ( 4n ) - 2 (5n) - 2 (-3) = 25

3 + 12n - 10n + 6 = 25               (Product of two same signs is positive)

3 + 2n + 6 = 25                          (Subtract: 12n - 10n = 2n)

2n + 3 + 6 = 25                          (Apply commutative property of addition : a+b=b+a)

2n + 9 = 25                                (Add: 3 + 6 = 9)

2n + 9 - 9 = 25 - 9                      (Subtract 9 from each side)

2n  = 25 - 9                                (Simplify)

2n  = 16                                     (Subtract: 25 - 9 = 16)

n = 8                                          (Simplify)