What is the domain of (4/(a+1))-(5/a) = (20/(a^2+a))? Algebra Expressions, Equations, and Functions Domain and Range of a Function 1 Answer Rafael Oct 26, 2015 a={-25} Explanation: [1]" "4/(a+1)-5/a=20/(a^2+a) Combine 4/(a+1) and -5/a by making them have the same denominator. [2]" "(4(a))/(a(a+1))-(5(a+1))/(a(a+1))=20/(a^2+a) [3]" "(4(a)-5(a+1))/(a(a+1))=20/(a^2+a) [4]" "(4a-5a-5)/(a^2+a)=20/(a^2+a) [5]" "(-a-5)/(a^2+a)=20/(a^2+a) Multiply both sides by (a^2+a) to remove the denominator. [6]" "cancel(a^2+a)((-a-5)/cancel(a^2+a))=cancel(a^2+a)(20/cancel(a^2+a)) [7]" "-a-5=20 [8]" "-a=25 [9]" "color(blue)(a=-25) Answer link Related questions How do you determine if (-1, 4), (2, 8), (-1, 5) is a function? What is the domain for f(x)=2x-4? What is the domain and range for (3,1), (1,-4), and (2, 8)? What is the domain and range of a linear function? Is domain the independent or dependent variable? How do you find the domain and range of a function in interval notation? How do you find domain and range of a rational function? How do you find domain and range of a quadratic function? How do you determine the domain and range of a function? What is Domain and Range of a Function? See all questions in Domain and Range of a Function Impact of this question 1713 views around the world You can reuse this answer Creative Commons License