Help on 9 & 10 please!

Step-by-step explanation:

9. x and z are equal. y+z=90

   148-x=180 x+148 are supplementary

   -148    -148 Subtract 148 from both sides to isolate x

         x=32 degrees

         z=32 degrees b/c x and z are equal

 y+z=90 y and z are complementary

 y+(32)=90 Substitute 32 in for z

   -32     -32

 y         =58 degrees

10. (4x-25)=(2x+7) B/c of the bisection, the two angles are equal.

     4x-25  =2x+7 Remove parenthesis

      -2x       -2x Subtract 2x from both sides

     2x-25  =    +7

          +25       +25 Add 25 to both sides to isolate x

    2x         =     32

     /2                 /2 Divide both sides by 2 to isolate x

     x            =     16

 (4(16)-25)+(2(16)+7)=78 degrees Substitute 16 into the equation, this time adding the values instead of setting them equal to get the angle measure requested.

11. (6x-47)+(x+4)=90 Angles that are complementary add up to 90 degrees

    7x-43            =90 Add like terms

         +43             +43 Add 43 to both sides to isolate x

   7x                    =133

   /7                       /7 Divide both sides by 7 to isolate x

     x                     =19

((19)+4)=23 degrees Substitute x into the angle measure requested

12. 180=2x-9+x Use the words to help you determine what each value is.

     180=3x-9 Add like terms

     +9        +9 Add 9 to both sides to isolate x

     189=3x

     /3     /3 Divide both sides by 3 to isolate x

     63=x

 2(63)-9=177 degrees Substitute 63 into x to find the requested angle measure.