Answer:
Series combination:
Equivalent resistance =10Ω
Parallel combination:
Equivalent resistance 
Explanation:
Resistance: Resistance is the ratio of voltage to the current.

R = resistance 
I = current
V= potential difference(voltage)
There are two types of resistance combinations.
- series combination
- parallel combination.
Series combination: If the ending point of one resistance is connected to the starting point of other resistance that combination is known as series combination.
If R₁,R₂ and R₃  are connected in series combination.
Then equivalent resistance = R₁+R₂+R₃
Parallel combination: If the ending point and the starting point of the all resistance are the same points that combination is known as parallel combination.
If R₁,R₂ and R₃  are connected in parallel combination.
Then equivalent resistance  
Here R₁=7Ω and     R₂=3Ω
If R₁ and R₂  connected in series combination
Then equivalent resistance = (7+3) Ω
                                             =10Ω
If R₁ and R₂  connected in parallel combination
Then equivalent resistance 
                                               