3x-4 or = to 7

plz help

3 + 4 = 7  which is true.

Step-by-step explanation:

Whenever you have an equation with a plain variable (that is, no exponent included), there is only one number that will work when substituted for x.

To solve it, you have to "undo" what is done to the variable. You also go in the reverse order of operations, so you do the addition/subtract first, then multiplication/division.

You also have to do the same to both sides, kind of like keeping a balance scale in balance.

In this case, we subtract 4 from both sides first:

3x + 4 -4 = 7 - 4

The + 4 - 4 cancel each other out, so you get:

3x = 3

3x means "3 times x" so you divide by 3 to undo it. I will use the / to indicate division:

3x / 3 = 3 /3  

so 1x = 1.

Since 1x is "1 times x" it is the same as x by itself, so:

x=1

AND, if we substitute 1 back into the original equation (the asterisk stands for multiply):

3 * 1 + 4 = 7

3 * 1 is 3, so:

3 + 4 = 7     which is true.

1 is the only number that works.

Hope this helped.

i think it is c, not positive though

step-by-step explanation:

30 miles

step-by-step explanation:

we know that 60 seconds equals 1 minute and 60 minutes 1 hour

44 ft       60 sec     60 min     158400   ft

  *   *   =

1 sec       1 min       1 hour         hour

we know that there are 5280 ft per mile

158400   ft       1 mile         30 miles

  *   =

1   hour               5280 ft     1 hour

so in 1 hour   it can travel 30 miles