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If f(x) is a linear function ,f(-1)=-3 , and f(4)=-5 , find an equation for f(x)

User Elinore
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1 Answer

11 votes

Answer:

f(x) = -²/₅ x - ¹⁷/₅

Step-by-step explanation:

The equation of the linear function: f(x) = mx + b

f(-1) = -3 ⇒ -3 = m(-1) + b ⇒ m = b + 3

f(4)=-5 ⇒ -5 = m×4 + b

-5 = 4(b+3) + b

-5 = 4b + 12 + b

5b = -5 - 12

b = -¹⁷/₅

m = -¹⁷/₅ + 3 = -¹⁷/₅ + ¹⁵/₅ = -²/₅

Therefore the function:

f(x) = -²/₅ x - ¹⁷/₅

User Pfwd
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