Question

решите уравнение а) 5^x+3×5^x-2=140 б) 3×3^2x -10×3^x+3=0

Answer 1

5^x+3*5^(x-2)=140.  5^x+3*5^x/5^2=140. 5^x=y.  y+3y/25=140,  1,12y=140, y=125   5^x=5^3, x=3