Maths problem!!!! need help!!!!!! urgent

p=πr + 2r + 2A
p=84
r=6.7

part a)work out the value of A.give your answer correct to 2 significant figures
part b)Make r the subject of the formula p=πr + 2r + 2A

can you please show working

Thanks

p = πr + 2r + 2A
84 = π(6.7) + 2(6.7) + 2A

2A = 84 - (6.7)(2+π)
2A = 84 - (6.7)(5.141592654)
2A = 49.5513
A = 24.78

A = 25 to 2 sf

to make r the subject, do some rearranging:

p = πr + 2r + 2A
p-2A = πr + 2r
(p-2A) = r(π + 2)
r = (p-2A) / (π + 2)

check:
r = (84-49.55) / (5.14159)
r = 6.70, as we had before!