# Domain and Range

by Linda Baha
(Tucson, AZ)

3 + 4 = 7 (-7) + (3) = 10 -(7 + 3) = 10 (-17 + 11) = -(11 + 17) = -29 need to find the domain and range

### Comments for Domain and Range

 Aug 09, 2011 Domain and Range by: Staff The question: by Linda Baha (Tucson, AZ) 3 + 4 = 7 (-7) + (3) = 10 -(7 + 3) = 10 (-17 + 11) = -(11 + 17) = -29 need to find the domain and range The answer: Some definitions: For every relation: The domain is the input (every possible input value): the first number in a set of ordered pairs The range is the output (every possible output value): the second number in a set of ordered pairs For example: The following relation is a set of ordered points {(1,20) , (2,30) , (3,40) , (4,50)} The domain is (every possible input value): 1, 2, 3, 4 The range is (every possible output value): 20, 30, 40, 50 The following relation is a function f(x) = x² The DOMAIN is (every possible input value): x = all Real Numbers Using subset notation: Dom( f(x) ) = {x ∈ ℝ} Using interval notation: Domain: (-∞,∞) The RANGE is (every possible output value): f(x) = all Real Numbers greater than or equal to 0 Using subset notation: Ran( f(x) ) = {f(x) ∈ ℝ│f(x) ≥ 0 } Using interval notation: Range: [0,∞) Your problems: Strictly adhering to the definition of domain and range 3 + 4 = 7 Assuming this represents the Ordered pair: {3 + 4, 7} Domain: {3 + 4} Range: {7} (-7) + (3) = 10 Assuming this represents the Ordered pair: {(-7) + (3), 10} Domain: {(-7) + (3)} Range: {10} -(7 + 3) = 10 Assuming this represents the Ordered pair: {-(7 + 3), 10} Domain: {-(7 + 3)} Range: {10} (-17 + 11) = ? Assuming this represents the Ordered pair: {(-17 + 11) , ?} Domain: {(-17 + 11)} Range: {?} -(11 + 17) = -29 Assuming this represents the Ordered pair: {-(11 + 17) , -29} Domain: {-(17 + 11)} Range: {-29} Thanks for writing. Staff www.solving-math-problems.com