Answer:
Step-by-step explanation:
Step one:
given data
charges=$90
installation=$9 per square yard
total cost of installation= $810
let x represents the number of square feet
Step two:
The expression for the installation cost is given as
810=9x+90------------1
solve for x, collect like terms
810-90=9x
720=9x
divide both sides by 9 we have
x=720/9
x=11.11 square yard