Simply simplify multiplication expressions with a positive exponent
You said X = (5y+1) / (y-2)
Multiply each side by (y-2):
X(y-2) = (5y+1)
Eliminate parentheses:
Xy - 2X = 5y + 1
Add 2X to each side:
Xy = 5y + 1 + 2X
Subtract 5y from each side:
(X-5)y = 1 + 2X
Divide each side by (X-5):
<em>y = (1+2X) / (X-5) </em>
Consider the contrapositive of the statement you want to prove.
The contrapositive of the logical statement
<em>p</em> ⇒ <em>q</em>
is
¬<em>q</em> ⇒ ¬<em>p</em>
In this case, the contrapositive claims that
"If there are no scalars <em>α</em> and <em>β</em> such that <em>c</em> = <em>α</em><em>a</em> + <em>β</em><em>b</em>, then <em>a₁b₂</em> - <em>a₂b₁</em> = 0."
The first equation is captured by a system of linear equations,

or in matrix form,

If this system has no solution, then the coefficient matrix on the right side must be singular and its determinant would be

and this is what we wanted to prove. QED
Answer:
Only about 1/3 of the pencils have erasers.