Solved on Jan 18, 2024

Find the value of aa when f(x)=2x39x2+7x+a=0f(x)=2x^3-9x^2+7x+a=0 with x=2x=2.

STEP 1

Assumptions
1. The function given is f(x)=2x39x2+7x+a f(x) = 2x^3 - 9x^2 + 7x + a .
2. We need to find the value of a a when x=2 x = 2 and f(x)=0 f(x) = 0 .

STEP 2

We will substitute x=2 x = 2 into the function f(x) f(x) and set the function equal to zero.
f(2)=2(2)39(2)2+7(2)+a f(2) = 2(2)^3 - 9(2)^2 + 7(2) + a

STEP 3

Calculate the value of 23 2^3 which is 2×2×2 2 \times 2 \times 2 .
23=8 2^3 = 8

STEP 4

Calculate the value of 9(2)2 9(2)^2 which is 9×2×2 9 \times 2 \times 2 .
9(2)2=9×4=36 9(2)^2 = 9 \times 4 = 36

STEP 5

Calculate the value of 7(2) 7(2) which is 7×2 7 \times 2 .
7(2)=14 7(2) = 14

STEP 6

Substitute the calculated values back into the function.
f(2)=2(8)36+14+a f(2) = 2(8) - 36 + 14 + a

STEP 7

Multiply 2 2 by 8 8 .
2(8)=16 2(8) = 16

STEP 8

Now, combine all the constant terms together.
f(2)=1636+14+a f(2) = 16 - 36 + 14 + a

STEP 9

Simplify the constant terms by performing the arithmetic operations.
f(2)=20+14+a f(2) = -20 + 14 + a
f(2)=6+a f(2) = -6 + a

STEP 10

Since we know that f(2)=0 f(2) = 0 , we can set the expression equal to zero and solve for a a .
0=6+a 0 = -6 + a

STEP 11

Add 6 6 to both sides of the equation to isolate a a .
0+6=6+a+6 0 + 6 = -6 + a + 6

STEP 12

Simplify the equation to find the value of a a .
a=6 a = 6
The value of a a when f(x)=0 f(x) = 0 and x=2 x = 2 is a=6 a = 6 .

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