PLEASE. HELPhshdjfnhdhe

x+2y= -10eqn(i)

3x-y=12eqn(ii)

multiply the eqn(ii) by 2

x+2y= -10

6x-y=12

or, 7x=14

or, x=14/7

or, x=2

now, substituting the value of x=2 in eqn(i)

x+2y= -10

or, 2+2y= -10

or, 2y= -10-2

or, 2y= -12

or, y= -12/2

or, y= -6

therefore the equation is proved

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

idk lol xd

step-by-step explanation:

ez do it yourself lazy