(0.49) 4 x (0.343) 4 ÷ (0.2401) 4 = (70 ÷ 100) ? + 3

(70 ÷ 100) ^{? + 3} = (0.49)⁴ x (0.343)⁴ ÷ (0.2401)⁴
(0.7) ^{? + 3} = (0.49 x 0.343/0.2401)⁴
(0.7)^{? + 3} = (0.7)⁴
On comparing the exponents both sides, we get
? + 3 = 4
∴ ? = 4 - 3 = 1