simplify 5/(m-1)-2/(m-3)
The original denominators must be nonzero: m ∈ ℝ \ { 1, 3 }
Let's sum the fractions: 5m -1 -2m -3
ⓘ To add fractions, put them over the same denominator, then add the numerators: 5m -1 -2m -3 = 5·(m -3) -2·(m -1)(m -1)·(m -3)
5·(m -3) -2·(m -1)(m -1)·(m -3)
ⓘ Expand by multiplying each term inside the parentheses: 5·(m -3) = 5m -15, -2·(m -1) = -(2m -2)
5m -15 -(2m -2)(m -1)·(m -3)
ⓘ A minus sign before a parenthesis changes the sign of each of its terms: -(2m -2) = -2m + 2
5m -15 -2m + 2(m -1)·(m -3)
ⓘ The numerator and the denominator are computed before the division: -15 + 2 = -13■Like terms are grouped by adding their coefficients: 5m -2m = 3m
▶Result:   3m -13(m -1)·(m -3)