Please help me subject math

i'll brainliest if you answer correctly

Step-by-step explanation:

1)

8 + (-4)

= 8 - 4

= 4

2)

-2/3 + (-5/6)

= -2/3 - 5/6

= -4-5/6

= -9/6

= -3/2

3)

(-9) (-12)

= 9 × 12

= 108

4)

-5 + (-5)

= -5 - 5

= - 10

5)

(8) (-4)

= 8 × -4

= -32

6)

(1/2) (2/5)

= 1/2 × 2/5

= 1/5

7)

12 + 14

= 26

8)

(13) (7)

= 13 × 7

= 91

9)

(-3/8) (3/4)

= -3/8 × 3/4

= -9/32

what

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!