Which pair of terms are not like terms? A. 4a and 7a
B. 3p^2q and -p^2q
C. 2mn and mn^2
D. -x and 3x

C.

Step-by-step explanation:

Like terms must have exactly the same variables and exactly the same exponents.

In C., you have mn and mn^2. That makes the variable parts not the same, so they are not like terms.

C.

x =±sqrt(1/3)

step-by-step explanation:

x+4/6x=1/x

multiply each side by 6x to get rid of the fractions

6x*(x+4/6x)=1/x*6x

distribute

6x^2 +4 = 6

subtract 4 from each side

6x^2 +4-4 = 6-4

6x^2 =2

divide by 6

6x^2/6 = 2/6

x^2 = 1/3

take the square root of each side

sqrt(x^2) = ±sqrt(1/3)

x =±sqrt(1/3)

c > -10.55

step-by-step explanation: