the cost of constructing a table x metres long varies partly as x and partly as x². If the costs gh¢ 300.00 when it is 3.0m long and gh¢ 275.00 when it is 2.5m long . Find the cost when the table is 5.5m long

Answer 1

c = a x + b x^2

300.00 = 3.0 a + 9.0 b ... multiplying by 5/6 ... 250.00 = 2.5 a + 7.5 b

275.00 = 2.5 a + 6.25 b

subtracting equations (to eliminate a) ... 25.00 = 1.25 b

solve for b , then substitute back to find a

use the values of a and b to find the cost of a 5.5 m table