Answer is NO. Not correct
Step by step
6x -2 (15 - 2x) = 10
Their first mistake is in their distributive multiplication (-4x) should be (+4x) as below
6x -30 + 4x = 10
6 (20) -30 +4 (20) = 10
120 -30 +80 = 10
90 + 80 = 10
170 = 10 does not equal, it not a solution
Solve
6x -2 (15 - 2x) = 10
6x -30 + 4x = 10
10x -30 = 10
10x = 10 + 30
10x = 40
x = 4
Check your work
6x -2 (15 - 2x) = 10
Substitute 4 in for x
6x -2 (15 - 2x) = 10
6(4) -30 +4(4) = 10
24 - 30 + 16 = 10
10 = 10
X = 4 is a solution
Problem solved