Plizzz helppp I don't know how to do it helpp

Lol I'll help you. So for the 1st problem, you need to subtract 7x from 4x but if your looking for and answer then x=2. For the 2nd problem subtract 3x-5x and 7 + 9 which brings you to -2x - 16 which means you would have to find x in this problem which means x has to be a negative. The negative answer is x= -32 since a negative x a negative is a positive. Which brings you to 16-16 and then 0. For the third one, you need to change the problem. Turn it into 5x - x = 4 + 8 which brings you to 4x = 12 making x =3. and for number 4 you need do the same as we just did and do 11x - 6x - 3x and then do 20 - 6 which brings you to 2x = 14 which makes  x=7.

Step-by-step explanation:

step-by-step explanation:

given perimeter: 28cm

length: 9cm

atp,

2(l+w)=p of the reactangle

2(9+x)=28

18+2x=28

2x=28-18

x=10/2

x=5

therefore width is 5 cm