a textbook store sold a combined total of 348 history and chemistry text books in a week the number of history textbooks sold was three times the number of chemistry books sold. How many textbooks of each type were sold?

2 1/2 feet

step-by-step explanation:

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.

step-by-step explanation:

x-intercept:

(

−

1

+

√

7

,

0

)

,

(

−

1

−

√

7

,

0

)

y-intercept:

(

0

,

−

6

)