Mathematics
Find the value of x:
(3 + 4) (32 + 42) (34 + 44) (38 + 48) (316 + 416) (332 + 432) = (4x - 3x)
Answer
We know the algebraic identity:
(a - b) (a + b) = a2 - b2
The given expression can also be written as,
(4 + 3) (42 + 32) (44 + 34) (48 + 38) (416 + 316) (432 + 332) = (4x - 3x)
To use our identity, we need a (4 - 3) term at the beginning. Since 4 - 3 = 1, multiplying the left side by (4 - 3) does not change its value:
∴ Given expression can be re-written as:
(4 - 3)(4 + 3) (42 + 32) (44 + 34) (48 + 38) (416 + 316) (432 + 332) = (4x - 3x)
From the algebraic identity,
(4 - 3) (4 + 3) = (42 - 32)
(42 - 32) (42 + 32) = (44 - 34)
(44 - 34) (44 + 34) = (48 - 38)
(48 - 38) (48 + 38) = (416 - 316)
(416 - 316)(416 + 316) = (432 - 332)
(432 - 332)(432 + 332) = (464 - 364)
464 - 364 = 4x - 3x
∴ x = 64
Hence, x = 64.