Answer:
To find the value of x that makes the equation 7^15 * 7^4 = 7^x true, you can use the properties of exponents.
In this case, you can apply the rule that when you multiply two numbers with the same base, you can add their exponents. So, for the equation:
7^15 * 7^4 = 7^x
You can combine the exponents on the left side:
7^(15 + 4) = 7^x
Now, you have:
7^19 = 7^x
For these two exponential expressions to be equal, the exponents must be equal:
x = 19
So, the value of x that makes the equation true is x = 19.