OG详解-OG4 数学1 Q13

The correct answer is 15​​. Since the number 5 can also be written as 5​1​, the given equation can also be written as x8​​ = 51​​. This equation is equivalent to 8x​​ =1​5​.Therefore, the value of8x​​ is 15​. Note that 1/5 and .2 are examples of ways to enter a correct answer. Alternate approach: Multiplying both sides of the equation x8​= 5  by 8 yields x = 40. Substituting 40 for x into the expression 8​x​ yields  840​​ , or 1​5​