Step-by-step explanation:
In this case, you input the value of y (y = 6) into the equation ( 2.5(y-x)= 0)
2.5(6-x) = 0
Open the bracket,
(2.5×6)-2.5x= 0
Collect like terms.
2.5x= 2.5×6
Divide both sides by the coefficient of x (2.5)
x = 6
So,
x= 6 is true.
.
Substituting 6 for x in the equation,
2.5(6-6)= 0
2.5•0 = 0
0= 0
Which is also true.
Answer:

Step-by-step explanation:
since a=lw, the area is (x^2-3x+7)(x+4)
1. distribute parentheses 
2. apply +(-a)=-a rule 
3. Simplify
Steps to simplify:





4. Add like terms 
5. Add like terms 
<span> A. x²+2 - a polynomial
B.(x⁸-2)/(x⁻²+3) rational function
C. 7x⁷-2x⁻⁴+3 (It has negative value of exponent, so it cannot be a polynomial.)
D.x^x-1 (x is an exponent it cannot be a polynomial)</span>