Math Help Needed please?

Question

Solve using the addition and multiplication principles~

1 + 4x < 21

The solution set is {x | x ? ? }

Answer 1

Go with BigMac...he is%100 correct

Answer 2

1 + 4x &lt; 21

4x &lt; 20

x &lt; 5

Assuming no other constraints, x is between (-∞) and 5

Answer 3

is it the solution is like this

4x &lt; 21 - 1

4x &lt; 20

x  &lt; 20/4

x &lt; 5

Answer 4

1 + 4x &lt; 21

sub 1 from each side

4x &lt; 20

divide by 4

x &lt; 5

so the solution set is

{x|x &lt; 5}

Answer 5

I think I know

1 + 4x = 5x &lt; 21, therefore 21 divide 5 = 4.2

OR

4x &lt; 21 - 1 = 20

20 divide 4 = 5

either x is 4.2 or 5

Answer 6

the answer is x&lt;5, what grade r u in?