ANSWER:
21Ω
STEP-BY-STEP EXPLANATION:
Given:
R1 = R2 = R3 = 7Ω
The resistance in a series circuit has the following equation
[tex]R_{eq}=R_1+R_2\ldots+R_n[/tex]We replacing in this case:
[tex]\begin{gathered} R_{eq}=R_1+R_2+R_3 \\ R_{eq}=7+7+7 \\ R_{eq}=21\Omega \end{gathered}[/tex]The equivalent resistance of the circuit is 21Ω
