Algebra word problem-hiv infection?

in 1998 there were 47 million people worldwide who had been infected w/ HIV. at that time the infection rate was 5.8 million ppl/yr. how would i write this problem into a linear function that shows the total # of ppl in millions who were infected w/ HIV "x" yrs after 1998? any help is appreciated. thank you.

you should use the function form y=mx+b

m tells us the rate at which the infection increases (5.8)
and b tells us the initial number of people infected (47).

so the equation is y=5.8x+47 (with the numbers in millions)

Shouldn't it be y = 5.8(x-1998)+47 ? Don't ask the user of the equation to remember to subtract 1998. The best-answer equation is useful mainly when precision is a problem. Report It

Sigh...They're even trying to indoctrinate you in math class.

i = 58,000,000*x + 47,000,000

where "i" is the number infected and "x" is the number of years after 1988.

Total Infected at "X" years after 1998 = y

y = 5,800,000 *(x) + 47,000,000

Linear equantion general form y = mx +b

The equation of a linear function is y = mx + b.

m is given to be 5.8 mp/yr (million people per year). x is the number of years, and y the number of infected people.

An (x,y) point on this function is given by (1998,47); that is, in year 1998, 47 mp were infected. Plug that into y = mx + b:

47 = 5.8*1998 + b,

so that b = -11541.4

So the formula is

y = 5.8* x - 11541.4

Substitute x = 1998 to see if you get 47.

By the way, this would not be realistic. The rate at which people get infected is clearly some kind of linear function of the number of people who already are infected, as people pass HIV to other people. This suggests a geometric or exponential growth rate instead.