Add the expression (algebra)
1. (2x + 5) + (x + 4)
2. (3y - 5) + (2y + 4)
3. (4a + 12) + (-6a - 13)

Subtract the expression
4. (3x + 3) - (4x + 6)
5. (8y - 7) - (y - 4)
6. (3b + ) - (2b + 7)

Factor each expression
7. 16y - 8
9. -12c - 8

Step-by-step explanation:

1.

2.

3.

4.

5.

6. Incomplete (3b + ?)

7.

8.

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