JAMB - Mathematics (2015 - No. 55)
Solve the equation
\( 5^{(x − 2)} = (1 ÷ 125)^{(x +3)}\)
\( 5^{(x − 2)} = (1 ÷ 125)^{(x +3)}\)
3/2
− 7/4
4/7
7/4
Explication
\( 5^{(x − 2)} = (125^{−1} )^{(x + 3)}\\
5^{(x − 2)} = (5− 3)^{x + 3}\\
5^{(x − 2)} = 5^{− 3x − 9}\\
x + 3x = − 9 + 2\\
4x = − 7\\
x = \frac{−7}{4} \)
5^{(x − 2)} = (5− 3)^{x + 3}\\
5^{(x − 2)} = 5^{− 3x − 9}\\
x + 3x = − 9 + 2\\
4x = − 7\\
x = \frac{−7}{4} \)