Question 9713
The length is 5 meters greater than its width: {{{ L = W + 5 }}}. The length is already longer, so it makes sense to add 5 meters to the shorter width to equal the length.


The perimeter is 150 meters. So: {{{ 2L + 2W = 150 }}} <------ Start here.


{{{ 2(W + 5) + 2W = 150 }}} <------- Since we were given word about the relationship between length and width, we perform a substitution. Since {{{ L = W + 5 }}}, we can replace the L with the {{{ W + 5 }}} in the perimeter equation. TIP: When substituting an expression for a variable, it is ALWAYS THE BEST to put the expression inside a parentheses.


{{{ 2W + 10 + 2W = 150 }}} <----------- Distributed


{{{ 4W + 10 = 150 }}} <-------- Combined like terms


{{{ 4W = 140 }}} <---------- Subtracted 10 from both sides.


{{{ W = 35 }}} <-------- The width is 35 meters. If the length is 5 meters greater than the width, then the length is 35 + 5 = 40 meters.