Multiply everything in the parenthesis by a.
ac + ab = d
Subtract ab from both sides.
ac = d - ab
Divide a on both sides.
c = d - ab / a
Hope this helps!
You would divide 44 by 16 so the wing span is 2.75 ft.
There are 3 girls .
9 students , 3 boys & 3 girls + another 3 boys because there are 3 more than girls so there are only 3 girls since you can't exceed 9 .
Fraction: 180/x = 3/100
cross multiply: 18000 = 3x
divide ea. side by 3: x = $6,000
Amt. of sales = $6,000