The answer is \(2\frac{1}{5} =4x- \frac{4}{5}\), x = 3/4 pound.
Let m be the weight of math textbook.
Let x be the weight of language arts class.
Math textbook weighs 4/5 of a pound less than 4 times the weight of the book for language arts class:
m = 4x - 4/5
Since \(m = 2 \frac{1}{5}\), then:
\(2\frac{1}{5} =4x- \frac{4}{5}\)
\(2 + \frac{1}{5}=4x- \frac{4}{5}\)
\(2+ \frac{1}{5} + \frac{4}{5}=4x\)
\(2+ \frac{1+4}{5}=4x\)
\(2+ \frac{5}{5}=4x\)
\(2+1=4x\)
\(3=4x\)
\(x= \frac{3}{4}\)
