-0.4x-1.2>0.8?

So treat > as =

-0.4x - 1.2 = 0.8

Solve as any system of equations. Isolate the x term

-0.4 = 2.0

Now, put back the > sign

-0.4x > 2.0

Divide by -1. This switches the sign > to <

0.4x < 2.0

Isolate x

x< 5

Why does the sign flip. Well a>b is the same as -a<-b. Think about it. 2>1, but -2<-1.

It wants you to find a valu of 'x' that satisfies the inequality (>) .

Treat inequality signs like an 'equals' , except when dividing by a fraction or negative number. There upon turn the sign around.

-0.4 x - 1.2 > 0.8

Add '1.2' to both sides

-0.4x > 0.8 + 1.2

-0.4 x > 2.0

divide both sides by -0.4 ( Change the sign around)

--0.4 x / -0.4 < 2.0 / -0.4

x < -5

-0.4x - 1.2 > 0.8

Collect the like term

-0.4x > 0.8 + 1.2

-0.4x > 2

Divide both side by -0.4

-0.4x/-0.4 < 2/(-0.4)

∴ x < - 5

Note: if you divide both side by a negative value in inequality then the sign will change from > to < and vise versal.

when we divide by -0.4 the sign of inequality changes because its like,

3>-5 but when this is multiplied by -1 it becomes -3<5.

So,

x+3<2

x<-1

This is the answer

-4x - 12 > 8

- 20 > 4x

- 5 > x