I can someone help me Solve for x.

9

Step-by-step explanation:

They are similar triangles.  Since 6 is 1.5 times the four, x has to be 1.5 times the 6.

6*1.5=9

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.