# Thread: Definite Integration: int[3,9][f(x)]dx = 7; find int[3,9][2*f(x) + 1]dx

1. ## Definite Integration: int[3,9][f(x)]dx = 7; find int[3,9][2*f(x) + 1]dx

Given that ∫ (9 upper limit and 3 lower limit) f(x) dx = 7
Evaluate
∫ (9 upper limit and 3 lower limit) 2f(x) +1 dx

Have no idea where to start

2. Originally Posted by sojeee
Given that ∫ (9 upper limit and 3 lower limit) f(x) dx = 7
Evaluate
∫ (9 upper limit and 3 lower limit) 2f(x) +1 dx

Have no idea where to start
$\displaystyle{\int [a * f(x)]dx \ = \ a * \int f(x)dx}$

3. Originally Posted by Subhotosh Khan
$\displaystyle{\int [a * f(x)]dx \ = \ a * \int f(x)dx}$

4. Originally Posted by sojeee
Given that ∫ (9 upper limit and 3 lower limit) f(x) dx = 7
Evaluate
∫ (9 upper limit and 3 lower limit) 2f(x) +1 dx
Have no idea where to start
I find your lack of grouping symbols makes this hard to read.
If this is a correct reading then: $\large{\int_3^9 {(2f(x) + 1)dx} = 2\int_3^9 {f(x)dx + } \int_3^9 {1dx} }$

5. Originally Posted by sojeee
You can factor out any constant in front of the integral sign!

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