simplifing by combining like terms...?

Question

7x+3x-15

(3y+4)(-1)+y

2(c-3)-3(c+1)

-11/4y-1/6y

help me please

Answer 1

Question 1
10x - 15

Question 2
(3y + 4) (- 1) + y -------as is written
= - 3y - 4 + y
= - 2 y - 4
= (- 2) (y + 2)

Question 3
2c - 6 - 3c - 3
= - c - 9
= - (c + 9)

Question 4
Assume question is:-
(- 11 / 4) y - (1 / 6) y
(- 33 / 12) y - (2/12) y
(- 35 / 12) y

Answer 2

Add the ones with letters (aka variables) to the other ones with letters.

first one ....... 10x -15

second one do the multiplication first, then combine
=-3y -4+y
=-2y +4 <----- this is the answer

multiply then combine on the third one

=2c -6-3c-3
=-c -9 <---- this is the answer

fourth one, get them as the same base

-11/4y-1/6y

use 24y as your base

-66/24y - 4/24 y

-70/24y

simplify

-35/12 y