Respuesta :

Answer:

A = 45a + 63 square units

Step-by-step explanation:

Formula of the area of a triangle: [tex]\frac{1}{2}bh[/tex]

Plug in givens:

[tex]\frac{1}{2}(18)(5a+7)\\ \frac{1}{2}(18)(5a+7)\\9(5a+7)\\45a + 63[/tex]