Answer:
B: x=-5 and x=4
Step-by-step explanation:
f(x)= x^2 + x -20
To find the zeros we replace f(x) with 0
now we solve for x
LEts factor x^2 + x -20
sum is +1 and product is -20
5 * (-4)= -20
5 + (-4) = +1
x^2 + 5x - 4x - 20 = 0
(x^2 + 5x)+(- 4x - 20) = 0
x(x+5) -4 (x+5) = 0
(x-4)(x+5)=0
Set each factor =0 and solve for x
x- 4 =0 so x=4
x+5 =0 so x=-5
x=-5 and x=4
NOTES:
Use the equation y = mx + b where m is the unit rate and b is the one-time flat fee
1. Answer:
<u>Step-by-step explanation:</u>
coffee maker costs $70 - this is a one-time flat fee
it costs $0.20 per cup of coffee - this is the unit rate
y = 0.20x + 70
y = 0.20(0) + 70 → y = 0.00 + 70 → y = 70.00
y = 0.20(1) + 70 → y = 0.20 + 70 → y = 70.20
y = 0.20(2) + 70 → y = 0.40 + 70 → y = 70.40
y = 0.20(3) + 70 → y = 0.60 + 70 → y = 70.40
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2. Answer:
<u>Step-by-step explanation:</u>
shoes costs $3.00 - this is a one-time flat fee
it costs $1.50 per game of bowling - this is the unit rate
y = 1.50x + 3.00
y = 1.50(1) + 3.00 → y = 1.50 + 3.00 → y = 4.50
y = 1.50(2) + 3.00 → y = 3.00 + 3.00 → y = 6.00
y = 1.50(3) + 3.00 → y = 4.50 + 3.00 → y = 7.50
y = 1.50(4) + 3.00 → y = 6.00 + 3.00 → y = 9.00
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3. Answer: Negative
<u>Step-by-step explanation:</u>
As the x-values increase, the y-values decrease. Opposite directions results in a negative slope.
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4. Answer: Gym A → y = 20x + 50 Gym B → y = 25x + 30
<u>Step-by-step explanation:</u>
Use the slope formula: . Then choose ONE of the points and input the point (x₁, y₁) and slope (m) into the Point-Slope formula: y - y₁ = m(x - x₁) and solve for y.
Gym A: (x₁, y₁) = (1, 70) and (x₂, y₂) = (2, 90)
y - 70 = 20(x - 1)
y - 70 = 20x - 20
y = 20x + 50
Gym B: (x₁, y₁) = (1, 55) and (x₂, y₂) = (2, 80)
y - 55 = 25(x - 1)
y - 55 = 25x - 25
y = 25x + 30