Answer:176 psychology textbooks and 98 Biology textbooks were sold.
Step-by-step explanation:
Let x represent the number of psychology textbooks that were sold.
Let y represent the number of biology textbooks that were sold.
textbook store sold a combined total of 274 psychology and biology textbooks in a week. This means that
x + y = 274 - - - - - - - - - - -1
The number of psychology textbooks sold was 78 more than the number of biology textbooks sold. This means that
x = y + 78
Substituting x = y + 78 into equation 1, it becomes
y + 78 + y = 274
2y = 274 - 78
2y = 196
y = 98
x = y + 78 = 98 + 78
x = 176
An integer is a whole number and the product of numbers means to multiply them. So so we know that:
x * y = x - 50
So the product (x * y) is 50 less than one of the integers ( x - 50)
I can divide both sides by x:
y = (x - 50) / x where x is not zero
y = x/x - 50/x
y = 1 - 50/ x
x can no longer be zero since you cannot divide by zero
the only way for y to be a whole number is if 50/x is a whole number. 50/x can onky be a whole number if x is a factor of 50. so take any factor of 50 and that will be possible answers.
factors of 50: 1,2,5,10,25,50
these would be possible x values. To to find corresponding y values plug in x
y = 1 - 50/1
y = 1 - 50
y = -49
So first pair is (1, -49)
do the same for the rest and get
(2, -24)
(5, -9)
(10, -4)
(25, -1)
(50, 0)
11+(19+6)= (11+19)+6 so it's the associative property
Answer:
Wheres the graph? Or is the numbes that are on the graph im really confused?
