Answer:
Third option <3, 9>
Explanation:
u and v are two vectors and we know the Cartesian components of these vectors.
We must find the sum of u + v.
If we have the Cartesian components of both vectors then the sum of both is done by adding the components of u with the components of v.
![u = <1, 3>\\v = <2, 6>](https://img.qammunity.org/2020/formulas/mathematics/middle-school/hc3v2tz1ymkoxd2k2z13d26vkjiivu6io2.png)
![u + v = (1 + 2) i + (3 + 6) j](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qjcp3ntfn9cjlubv8k82kqxky3wqzu5y0b.png)
Where i is the vertical component and j is the horizontal component
Then u + v is
![u + v = (3) i + (9) j](https://img.qammunity.org/2020/formulas/mathematics/middle-school/rzzi8lhm16ss7gxr3m6eozkrp0tu8jmp2i.png)
![u+v = <3, 9>](https://img.qammunity.org/2020/formulas/mathematics/middle-school/plviyo9w459xao8aa9io4ptkcf8aludym6.png)