Hello from MrBillDoesMath!
Answer:
x = 19
Discussion:
Both sides are logarithms to the same base, namely 20 , which implies the expressions in x (what we are taking logarithms of) must be equal. So we need to solve
4x - 10 = 3x + 9 => subtract 3x from both sides
4x-3x - 10 = 9 => add 10 to both sides
x = 9 + 10 = 19
Thank you,
MrB