Problem page
a textbook store sold a combined total 217 of history and chemistry textbooks in a week. the number of chemistry textbooks sold was 57 less than the number of history textbooks sold. how many textbooks of each type were sold?

137 history books were sold

80 chemistry books were sold

Step-by-step explanation:

Let x = the number history textbooks sold by the textbook store in that week.

Let y = the number chemistry textbooks sold by the textbook store in that week.

The textbook store sold a combined total 217 of history and chemistry textbooks in the week. This means

x + y = 217 - - - - - -1

The number of chemistry textbooks sold was 57 less than the number of history textbooks sold. This means

x = 57 + y

Substituting x = 57+ y into equation 1. It becomes

57+y+y= 217

57 + 2y = 217

2y = 217 - 57 = 160

y = 160/2 = 80

x = 57 + y = 57 + 80

x = 137

137 history books were sold

80 chemistry books were sold

-8/2y-8=5/y+4-7y+8/y^2-16

we move all terms to the left:

-8/2y-8-(5/y+4-7y+8/y^2-16)=0

we can not solve this equation