Question

Determine o valor de x a) 16=256^x c) 10^-3x+21= 1 000 000 000^x-3

Answer 1

a) sabendo que
$16 = 4 ^{2} \\ 256 = {4}^{4}$
$4 {}^{2} = 4 {}^{4 \times x} \\ 2 = 4 \times x \\ x = 0.5$
c)
$10 {}^{21 - 3x} = 10 {}^{9 \times (x- 3)} \\ = 10 {}^{ - 3 + 9x - 27 } = 10 {}^{21 - 3x} \\ 21 - 3x = - 30 - + 9x \\ - 12x = - 51( - 1) \\ \times = 51 \div 12 = 4.25$