Algebra 1

Let m be the length of the middle part of the table. Let l be the length of a leaf. $m+l=5.5$ $m+2l=7$ Multiply the first equation by -1, and add the equations to eliminate m. $m+\ \ l=5.5\ \ \ \ \$ multiply by -1$\ \ \ \ -m-\ \ l=-5.5$ $m+2l=7\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \underline{m+2l=\ \ \ 7}$ $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ l=1.5$ Substitute 1.5 for l in either equation to solve for m. $m+l=5.5$ $m+1.5=5.5$ $m+1.5-1.5=5.5-1.5$ $m=4$