Question

Tentukan domain dari :
1. y = 4 - 5x
2. y = x²+3x-4
3. y =
4. y =
5. y =

tolong dibantu menjawab ya
trimakasih
manfaatkan poinnya dengan baik

Answer 1

Misal, y = f(x)

Df = {x ∈ R | f(x) ∈ R}

==========

1)
Df = {x ∈ R | 4 - 5x ∈ r}
Df = R
Df = (-~, ~)

2)
Df = {x ∈ R | x² + 3x - 4 ∈ R}
Df = {x ∈ R | (x + 4)(x - 1) ∈ R}
Df = R
Df = (-~, ~)

3)
Df = {x ∈ R | √2x - 6 ∈ R}
Df = {x ∈ R | 2x - 6 ≥ 0}
Df = {x ∈ R | 2x ≥ 6}
Df = {x ∈ R | x ≥ 6/2}
Df = {x ∈ R | x ≥ 3}

Df = {x | x ≥ 3, x ∈ R}
Df = [3, ~)

4)
Df = {x ∈ R | 1/(3x + 9) ∈ R}
Df = {x ∈ R | 3x + 9 ≠ 0}
Df = {x ∈ R | 3x ≠ -9}
Df = {x ∈ R | x ≠ -9/3}
Df = {x ∈ R | x ≠ -3}
Df = R - {-3}

Df = {x | -~ < x < -3, dan -3 < x < ~, x ∈ R}
Df = (-~, -3) U (-3, ~)

5)
Df = {x ∈ R | 1/(√8-2x) ∈ R}
Df = {x ∈ R | 8 - 2x > 0 }
Df = {x ∈ R | -2x > -8
Df = {x ∈ R | 2x < 8}
Df = {x ∈ R | x < 8/2}
Df = {x ∈ R | x < 4}

Df = { x | x < 4, x ∈ R}
Df = (-~, 4)