Quick math question e^{-.15x}=.42 my calculator is giving me 57.8334 but when i plug it back in to check my work its coming out as false why is it coming out false is my answer wrong : 0?

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g

Awindow has the shape of a rectangle with a semi circle at the top. find the approximate area of the window using the dimensions shown. 4ft by 8ft

Given a normal distribution with µ=20 and σ = 4, what is the probability that x> 24 x< 24 x< 24 or x> 24