I really need help with this one

28

Step-by-step explanation:

Since B is the midpoint of AC, that means AB = BC. That means 3x+4 = 5x-6. We can now set up an equation to solve for x:

3x+4 = 5x-6

3x+10 = 5x

10 = 2x

x = 5

Now that we know what x is, we can just plug x into the expression of AB and multiply it by 2:

(3*(5)+4)*2

=(15+4)*2

=19*2

=28

(side note: we could have plugged x into the expression of BC as well, but in this case plugging it into AB tends to be easier to solve)

Therefore, the length of AC is 28.

spinning a 1, 2, or 3. option d.

step-by-step explanation: when spinning a number graph up to 4, and aiming for any number less than 3, that automatically eliminates the number 4. now you have two numbers to spin on that are less than 3, but the number 3 is included in this question because it's no greater of an number than itself. i hope this you : )

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.