1. Show that (10a + 5)^2 = 100a(a + 1) + 25, for every a real number. How is this formula explaining the rule we have, to square

Question

1. Show that
(10a + 5)^2 = 100a(a + 1) + 25,
for every a real number. How is this formula explaining the rule we have, to square a number
which ends in 5, such as
25^2 = 625, 35^3 = 1225, 105^2 = 11025^2, etc. ?

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bonexptip 5 years 2021-08-30T11:05:30+00:00 1 Answers 8 views 0

Answers ( )

  1. thongdat2
    0
    2021-08-30T11:06:44+00:00
    Reply

    Answer:

     (10a+5)²= 100 a( a+1) + 25

    Step-by-step explanation:

    Explanation:-

    Given

         (10a+5)²

    By using (a+b)² = a² +2ab +b²

                       = (10a)²+ 2 × 10a× 5 + (5)²

                       = 100a² + 100a + 25

                       = 100 a( a+1) + 25

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )