Question

Select all of the equations for which x = 9 is a solution.

a) x^2 = 18
b) 7x = 42
c) 20 - x/11 = 1
d) 45 - 2x = 27
e) 3(1 + x) = 30

Answer 1

To determine which equations have x=9 as a solution, substitute 9 for x in each equation and check if both sides of the equation are equal. The equations for which x=9 is a solution are c), d), and e).

Step-by-step explanation:

To determine which equations have x=9 as a solution, we substitute 9 for x in each equation and check if both sides of the equation are equal.

a) x^2 = 18: 9^2 = 81 ≠ 18, so x=9 is not a solution.

b) 7x = 42: 7(9) = 63 ≠ 42, so x=9 is not a solution.

c) 20 - x/11 = 1: 20 - 9/11 = 20 - 9/11 = 20 - 9/11 = 20 - 9/11 = 19 1/11 = 1, so x=9 is a solution.

d) 45 - 2x = 27: 45 - 2(9) = 45 - 18 = 27, so x=9 is a solution.

e) 3(1 + x) = 30: 3(1 + 9) = 3(10) = 30, so x=9 is a solution.

Hence, the equations for which x=9 is a solution are c), d), and e).