Answer:
132 history textbooks, 87 chemistry textbooks
Step-by-step explanation:
[tex]C + H = 219\\C = H - 45\\[/tex]
[tex]1. H - 45 + H = 219\\2. 2H = 264\\3. H = 132[/tex]
H = 132,
C = 132 - 45 = 87
Answer: 87 Chemistry and 132 history textbooks.
Step-by-step explanation:
Let x represent the number of chemistry textbooks that was sold.
Let y represent the number of history textbooks that was sold.
The textbook store sold a combined total of 219 history and chemistry textbooks in a week. This means that
x + y = 219 - - - - - - - - - - - -1
The number of chemistry textbooks sold was 45 less than the number of history textbooks sold. This means that
x = y - 45
Substituting x = y - 45 into equation 1, it becomes
y - 45 + y = 219
2y = 219 + 45 = 264
y = 264/2 = 132
x = y - 45 = 132 - 45
x = 87
