3/5 of 300 is 180. 180 coupons were unused.
Step 1: Subtract 3x from both sides.
−x+7=−52
Step 2: Subtract 7 from both sides.<span><span><span><span>
−x</span>+7</span>−7</span>=<span><span>−52</span>−7</span></span><span><span>
−x</span>=<span>−59</span></span>
Step 3: Divide both sides by -1.<span><span><span>
<span><span>−x</span><span>−1</span></span></span></span>=<span><span><span><span>−59</span><span>−1</span></span></span></span></span><span>
x=59</span>
5.5/4=x/100
4x=550
x=137.5
the water tower is 137 ft. 6 in. tall.