Since Susan wants to make square flags, the smallest amount she can buy with no left over fabric will be half the width of the fabric. The most useful equation for Susan is therefore the first one, 2x^2 = 7x
2x^2=7x this is because if the side of the flag is x then the area she needs to cut is 2x^2 for 2 flags of area x•x since the width of the fabric is 7 this needs to be multiplied by x to figure out the least amount she could get without having left overs
