Evaluate : (7⁸×a¹⁰b⁷c¹²)/(7⁶×a⁸b⁴c¹²)
Solution:
Given, the expression is (78 × a10b7c12)/(76 × a8b4c12)
We have to evaluate the expression.
(78 × a10b7c12)/(76 × a8b4c12) = (78/76) × (a10/a8) × (b7/b4) × (c12/c12)
For any non-zero integers ‘a’ and ‘b’ and whole numbers m and n,
am ÷ an = am - n
Considering 78/76,
Here, a = 7, m = 8 and n = 6
m - n = 8 - 6 = 2
78/76 = 72
= 7 × 7
= 49
Considering a10/a8,
Here, m = 10 and n = 8
m - n = 10 - 8 = 2
a10/a8 = a2
Considering b7/b4,
Here, a = b, m = 7 and n = 4
m - n = 7 - 4 = 3
b7/b4 = b3
Considering c12/c12,
Here, a = c, m = 12 and n = 12
m - n = 12 - 12 = 0
c12/c12 = c⁰
We know a⁰ = 1
So, c⁰ = 1
Now, c12/c12 = 1
So, (78/76) × (a10/a8) × (b7/b4) × (c12/c12) = 49 × a2 × b3 × 1
Therefore, (78 × a10b7c12)/(76 × a8b4c12) = 49a2b3
✦ Try This: Evaluate : (92 × a8b5c2)/(32 × a5b2c)
☛ Also Check: NCERT Solutions for Class 7 Maths Chapter 13
NCERT Exemplar Class 7 Maths Chapter 11 Problem 85 (a)
Evaluate : (7⁸×a¹⁰b⁷c¹²)/(7⁶×a⁸b⁴c¹²)
Summary:
On evaluating (78 × a10b7c12)/(76 × a8b4c12) we get 49a2b3.
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