If-f-x-3-2x-2-3x-5-find-f-5-

Question Number 10874 by Saham last updated on 28/Feb/17

If f (x + 3) = {2 x}^{2} - 3 x + 5 . find f (5)

Answered by ridwan balatif last updated on 28/Feb/17

way 1

let : x + 3 = a \to a - 3 = x, then

f (a) = 2 {(a - 3)}^{2} - 3 (a - 3) + 5

f (a) = 2 (a^{2} - 6 a + 9) - 3 a + 9 + 5

f (a) = {2 a}^{2} - 15 a + 32

f (x) = {2 x}^{2} - 15 x + 32

f (5) = 2 \times 5^{2} - 15 \times 5 + 32

f (5) = 7

way 2

x + 3 = 5 \to x = 2

f (5) = 2 \times 2^{2} - 3 \times 2 + 5

f (5) = 8 - 6 + 5 = 7

Commented by Saham last updated on 28/Feb/17

God bless you sir .

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