The denominator of the second fraction can be factored as (a-2)(2a-7), then it becomes doable. You cancel the (2a-7) factors, and are left with:

Do note that you have erased the fact that a≠0 and a≠7/2, so you should always mention that.
There are seven SI base
units which are used in science, every unit has its own property or use:
Meter (length)
Kilogram (mass)
Second (time)
Kelvin (temperature)
Mole (amount of substance)
Ampere (electrical unit) and
Candela (luminous intensity)
<span>The SI unit of
measure for length (meter) would be most appropriate when we are measuring the
distance between two places or when we are taking measurement of something.</span>
Answer:

Step-by-step explanation:
=> 5x-4+2(x-4) = 16
Expanding the brackets
=> 5x-4+2x-8 = 16
Combining like terms
=> 5x+2x-4-8 = 16
=> 7x - 12 = 16
Adding 12 to both sides
=> 7x = 16+12
=> 7x = 28
Dividing both sides by 7
=> x = 4
What do you mean doubling? You can add 7+7+7 which equals 21.