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Algebra1 Adding and Subtracting Radical Expressions. Warm Up. Find the domain of each square-root function. 1) y = √(4x – 2) 2) y = -2√(x + 3) 3) y = 1 + √(x + 6). 1) exponential 2) quadratic. Adding and Subtracting Radical Expressions.
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Algebra1Adding and SubtractingRadical Expressions CONFIDENTIAL
Warm Up Find the domain of each square-root function. 1) y = √(4x – 2) 2) y = -2√(x + 3) 3) y = 1 + √(x + 6) 1) exponential 2)quadratic CONFIDENTIAL
Adding and Subtracting Radical Expressions Square-root expressions with the same radicand are examples of like radicals . Like radicals can be combined by adding or subtracting. You can use the Distributive Property to show how this is done: 2√4 + 4√5 = √5(2 + 5) = 7√5 6√x - 2√x = √x(6 - 2) = 4√x Notice that you can combine like radicals by adding or subtracting the numbers multiplied by the radical and keeping the radical the same. CONFIDENTIAL
Adding and Subtracting Square-Root Expressions Add or subtract. • 3√7 + 8√7 • = √7(3 + 8) = 11√7 • B) 9√y - √y • = √y(9 - 1) = 8√y • C) 12√2 - 4√11 • = √x(6 - 2) = 4√x • D) -8√(3d) + 6√(2d)+ 10√(3d) • = √(3d)(10 - 8) + 6√(2d) • = 2√(3d) + 6√(2d) The terms are like radicals. √y = √y. The terms are like radicals. The terms are unlike radicals. Do not combine. Identify like radicals. Combine like radicals. CONFIDENTIAL
Now you try! Add or subtract. 1a) 5√7 - 6√7 1b) 8√3 - 5√3 1c) 4√n + 4√n 1d) √(2s) - √(5s) + 9 √(5s) 1a) -√7 1b) 3√3 1c) 8√n 1d) √(2s) + 8√(5s) CONFIDENTIAL
Sometimes radicals do not appear to be like until they are simplified. Simplify all radicals in an expression before trying to identify like radicals. CONFIDENTIAL
Simplifying Before Adding or Subtracting Add or subtract. • √(12) + √(27) • = √{(4)(3)} + √{(9)(3)} • = √4√3 + √9√3 • = 2√3 + 3√3 • = √3(2 + 3) • = 5√3 Factor the radicands using perfect squares. Product Property of Square Roots Simplify. Combine like radicals. CONFIDENTIAL
B) 3√8 + √(45) = 3√{(4)(2)} + √{(9)(5)} = 3√4√2 + √9√5 = 3(2)√2 + 3√5 = 6√2 + 3√5 Factor the radicands using perfect squares. Product Property of Square Roots Simplify. The terms are unlike radicals. Do not combine. CONFIDENTIAL
C) 5√(28x) - 8√(7x) = 5√{(4)(7x)} - 8√(7x) = 5√4√(7x) - 8√(7x) = 5(2)√(7x) - 8 √(7x) = 10√(7x) - 8 √(7x) = 2√(7x) Factor 28x using a perfect square. Product Property of Square Roots Simplify. Combine like radicals. CONFIDENTIAL
D) √(125b) + 3√(20b) - √(45b) = √{(25)(5b)} + 3√{(4)(5b)} - √{(9)(5b)} = √(25)√(5b) + 3√4√(5b)-√9√(5b) = 5√(5b) + 3(2)√(5b) - 3√(5b) = 5√(5b) +6√(5b) - 3√(5b) = 8√(5b) Factor the radicands using perfect squares. Product Property of Square Roots Simplify. Combine like radicals. CONFIDENTIAL
Now you try! Add or subtract. 2a) √(54) + √(24) 2b) 4√(27) - √(18) 2c) √(12y) + √(27y) 2a) 5√6 2b) 9√3 2c) 5√(3y) CONFIDENTIAL
Geometry Application Find the perimeter of the triangle. Give your answer as a radical expression in simplest form. Write an expression for perimeter. • 12+5√7 + √(28) • = 12 + 5√7 + √{(4)(7)} • = 12 + 5√7 + √4√7 • = 12 + 5√7 + 2√7 • = 12 + 7√7 Factor 28 using a perfect square. Product Property of Square Roots Simplify. Combine like radicals. The perimeter is (12 + 7√7) cm. CONFIDENTIAL
Now you try! 3) Find the perimeter of a rectangle whose length is 2√b inches and whose width is 3√b inches. Give your answer as a radical expression in simplest form. 3) 10√b in. CONFIDENTIAL
Assessment • 14√3 - 6√3 • 9√5 + √5 • 6√2 + 5√2 - 15√2 1) 8√3 2) 10√5 3) -4√2 CONFIDENTIAL
4) 2√2 5) 17√3 6) 33√3 7) -√(5x) 8) 2√(7c)+18√(6c) 9) 8√(2t)-4√(3t) Simplify each expression. • √(32) - √(8) • 4√(12) + √(75) • 2√3 + 5√(12) - 15√(27) • √(20x) - √(45x) • √(28c) + 9√(24c) • √(50t) - 2√(12t) + 3√(2t) CONFIDENTIAL
10) Find the perimeter of the trapezoid shown. Give your answer as a radical expression in simplest form. 10) 12√2 in CONFIDENTIAL
Let’s review Adding and Subtracting Radical Expressions Square-root expressions with the same radicand are examples of like radicals . Like radicals can be combined by adding or subtracting. You can use the Distributive Property to show how this is done: 2√4 + 4√5 = √5(2 + 5) = 7√5 6√x - 2√x = √x(6 - 2) = 4√x Notice that you can combine like radicals by adding or subtracting the numbers multiplied by the radical and keeping the radical the same. CONFIDENTIAL
Adding and Subtracting Square-Root Expressions Add or subtract. • 3√7 + 8√7 • = √7(3 + 8) = 11√7 • B) 9√y - √y • = √y(9 - 1) = 8√y • C) 12√2 - 4√11 • = √x(6 - 2) = 4√x • D) -8√(3d) + 6√(2d)+ 10√(3d) • = √(3d)(10 - 8) + 6√(2d) • = 2√(3d) + 6√(2d) The terms are like radicals. √y = √y. The terms are like radicals. The terms are unlike radicals. Do not combine. Identify like radicals. Combine like radicals. CONFIDENTIAL
Sometimes radicals do not appear to be like until they are simplified. Simplify all radicals in an expression before trying to identify like radicals. CONFIDENTIAL
Simplifying Before Adding or Subtracting Add or subtract. • √(12) + √(27) • = √{(4)(3)} + √{(9)(3)} • = √4√3 + √9√3 • = 2√3 + 3√3 • = √3(2 + 3) • = 5√3 Factor the radicands using perfect squares. Product Property of Square Roots Simplify. Combine like radicals. CONFIDENTIAL
C) 5√(28x) - 8√(7x) = 5√{(4)(7x)} - 8√(7x) = 5√4√(7x) - 8√(7x) = 5(2)√(7x) - 8 √(7x) = 10√(7x) - 8 √(7x) = 2√(7x) Factor 28x using a perfect square. Product Property of Square Roots Simplify. Combine like radicals. CONFIDENTIAL
Geometry Application Find the perimeter of the triangle. Give your answer as a radical expression in simplest form. Write an expression for perimeter. • 12+5√7 + √(28) • = 12 + 5√7 + √{(4)(7)} • = 12 + 5√7 + √4√7 • = 12 + 5√7 + 2√7 • = 12 + 7√7 Factor 28 using a perfect square. Product Property of Square Roots Simplify. Combine like radicals. The perimeter is (12 + 7√7) cm. CONFIDENTIAL
You did a great job today! CONFIDENTIAL