<em>Look</em><em> </em><em>at</em><em> </em><em>the</em><em> </em><em>attached</em><em> </em><em>picture</em>
<em>H</em><em>ope</em><em> </em><em>it</em><em> </em><em>will</em><em> </em><em>help</em><em> </em><em>you</em>
A polynomial can have
constants
variables
exponents
that can be combined using addition, subtraction, multiplication and division ...
... except ...
... not division by a variable
Answer:
3*(5*x-7)-(15*x-21)=0
Step-by-step explanation:
3 • (5x - 7) - (15x - 21) = 0
Step 2 :
Equation at the end of step 2 :
0 = 0
Step 3 :
Equations which are always true :
Step-by-step explanation:

4(a+4)-2=34 (Multiply 4 with "A" and 4)
4a+16-2=34 (Do 16-2)
4a+14=34 (Minus 14 on both sides)
-14 -14
4a=20 (Divide 4a on both sides)
---------
4a 4a
=
a=5 (Answer: a=5)