B. 18
Explanation
The dot product or scalar product is an algebraic operation that takes two equal-length sequences of numbers (usually coordinate vectors), and returns a single number
it is given by.
[tex]\begin{gathered} u=(u_x,u_y) \\ v=(v_{_x},v_y) \\ u\cdot v=(u_xv_x+u_yv_y) \end{gathered}[/tex]so, we can find the dot product by multiplying the corresponding values in each vector and adding them together
Step 1
get the dot product
let
[tex]\begin{gathered} v_1=(2,4) \\ v_2=(-1,5) \end{gathered}[/tex]then
[tex]\begin{gathered} v_1\cdot v_2=(2\cdot-1)+(4\cdot5) \\ v_1\cdot v_2=-2+20 \\ v_1\cdot v_2=18 \end{gathered}[/tex]therefore, the answer is
B. 18
I hope this helps you
