Find the Indicated Sum or Difference $$\left( 7 z ^ { 2 } + 4 z \right) + \left( 8 z ^ { 2 } - 3 z + 9 \right)$$

Short Answer

Find the indicated sum or difference. $$\left( 7 z ^ { 2 } + 4 z \right) + \left( 8 z ^ { 2 } - 3 z + 9 \right)$$