1)P=2a+2b
b=?
2)S=ab/2
a=?
3)F=9/25C+32
C=?
4)I=E/R+r
E=?

1) P = 2a +2b

2b = P - 2a

b = P-2a /2

2) S =ab/2

ab = 2S

a= 2S/b

3) F =9/25C+32

F ( 25C+32 ) = 9

9 = 25FC + 32F

25FC = 32F - 9

C = 32F -9/ 25F

4) I = E/R+r

E = l ( R +r )

Пошаговое объяснение: