Question

Evaluate the dot product of (7,5)and (-5,4)

Answer 1

To evaluate the dot product of (7,5) and (-5,4)
this can be written in vector form as:
7i+5j and -5j+4j
thus the dot product will be:
(7i+5j)*(-5j+4j)
=(-5*7)+(5*4)
=-35+20
=-15
thus the answer is -15

Answer 2

Answer:

$(7i+5j)\cdot(-5i+4j)=-15$

Step-by-step explanation:

The given two points are:

$(7,5) and (-5,4)$

Writing them in vector form, we get

$(7i+5j) and (-5i+4j)$

Now, the product of these two vectors is given as:

=$(7i+5j)\cdot(-5i+4j)$

=$(-5)(7)+(5)(4)$

=$-35+20$

=$-15$

Therefore, $(7i+5j)\cdot(-5i+4j)=-15$

which is the required dot product.