Respuesta :

wegnerkolmp2741o

Answer:

x=13

Step-by-step explanation:

The sum of the angles of a triangle add to 180 degrees

3x+ 4x-1 +90 =180

Combine like terms

7x +89 = 180

Subtract 89 from each side

7x +89-89=180-89

7x =91

Divide each side by 7

7x/7 =91/7

x = 13