The answer is [tex] 2\frac{1}{5} =4x- \frac{4}{5} [/tex], 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 [tex]m = 2 \frac{1}{5} [/tex], then:
[tex] 2\frac{1}{5} =4x- \frac{4}{5} [/tex]
[tex]2 + \frac{1}{5}=4x- \frac{4}{5} [/tex]
[tex]2+ \frac{1}{5} + \frac{4}{5}=4x [/tex]
[tex]2+ \frac{1+4}{5}=4x [/tex]
[tex]2+ \frac{5}{5}=4x [/tex]
[tex]2+1=4x[/tex]
[tex]3=4x[/tex]
[tex]x= \frac{3}{4} [/tex]
