Respuesta :

abidemiokin

Answer:

-13

Step-by-step explanation:

Opposite of 9t = -9t

Taking the sum of 9t - 13 and -9t

Sum = 9t - 13 + (-9t)

Sum = 9t - 13 - 9t

Sum = 9t-9t - 13

Sum  = -13

Hence the expression in standard form is -13