What is the product of 2x + y and 5x – y + 3?

The product of 2x + y and 5x – y + 3 is 10x^2+ 3xy + 6x - y^2 + 3y

Step-by-step explanation:

The product of the two expressions can be expressed mathematically as;

(2x +y) (5x -y +3)

To obtain the product of these expressions, we simply expand the brackets as follows;

2x(5x -y +3) + y(5x -y +3)

= 10x^2 - 2xy + 6x + 5xy - y^2 + 3y

= 10x^2- 2xy + 5xy + 6x - y^2 + 3y

= 10x^2+ 3xy + 6x - y^2 + 3y

The product of 2x + y and 5x – y + 3 is thus 10x^2+ 3xy + 6x - y^2 + 3y

45

step-by-step explanation:

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12