To solve this expression, we need to substitute the given values of a, b, c, and d into the expression and simplify:
a/b - c + d = (7/8) / (-7/16) - 0.8 + 1/4
We can simplify the first term by dividing the numerator by the denominator and multiplying by the reciprocal:
(7/8) / (-7/16) = (7/8) * (-16/7) = -2
Substituting this value, along with the values of c and d, we get:
a/b - c + d = -2 - 0.8 + 1/4
Combining the constant terms, we get:
a/b - c + d = -2.8 + 1/4
To express this as a mixed number in simplest form, we first convert the decimal to a fraction by multiplying both the numerator and denominator by 100:
-2.8 + 1/4 = -280/100 + 25/100
Combining these fractions, we get:
-280/100 + 25/100 = -255/100
To express this as a mixed number, we divide the numerator by the denominator to get the whole number part, and express the remainder as a fraction of the denominator:
-255/100 = -2 55/100 = -2 11/20
Therefore, the answer in mixed number form is -2 11/20.