The cost of book case be $ 11.6.
<h3>What is linear equation?</h3>
A linear equation is an equation in which the highest power of the variable is always 1. It is also known as a one-degree equation. The standard form of a linear equation in one variable is of the form
Ax + B = 0.
Here, let the cost of book case be $ x
and the cost of pencil case be $ y
Now, Helen purchased 3 books and 2 pencils in $ 74.
3x + 2y = 74 .......(i)
Cost of pencil case $ 8 less than the book.
y - 8 = x ............(ii)
put the value of x in equation (i), we get
3(y - 8) + 2y = 74
3y - 24 + 2y = 74
5y = 74 + 24
5y = 98
y = 98/5
y = $ 19.6
put the value of y in equation (ii), we get
x = y -8
x = 19.6 - 8
x = $ 11.6
Thus, the cost of book case be $ 11.6.
Learn more about linear equation from:
brainly.com/question/11897796
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