(e) The price of a block of mahogany, given that a block of spruce costs 5 as much as a block of 9
mahogany, and Ted has bought 12 blocks of spruce and 15 blocks of mahogany for a total cost of $9750.
The equation given is
C(dollars)=w(blocks of spruce)y(cost of spruce)+x(mahogany)z(cost of mahogany)

“a term can be a signed number, a variable, or a constant multiplied by a + sign or j sign. in , the terms are 5x , 3y and 8. when a term is made up of a constant multiplied by a variable or variables, that constant is called a coefficient.” i hope this you.

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

source:  

i believe so, according to my "strange" way of figuring out weird math problems like this.