指數&對數問題

Q1 : 5^(x+1) + 5^x =24
5(5^x)+5^x=24
6(5^x)=24
5^x=4
log 5^x=log 4
x log 5=log 4
x=log 4 / log 5
= 0.86 (correct to 2 sign. fig.)

Q2 : 3^x X 4^x = 48
log (3^x X 4^x) = log 48
log 3^x + log 4^x = log 48
x log 3 + x log 4 = log 48
x (log 3 + log 4) = log 48
x log (3 X 4) = log 48
x log 12 = log 48
x = log 48 / log 12
= 1.56 (correct to 2 sign. fig.)

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