Integral of $$$5 x - 4$$$

Find $$$\int \left(5 x - 4\right)\, dx$$$.

Integrate term by term:

$${\color{red}{\int{\left(5 x - 4\right)d x}}} = {\color{red}{\left(- \int{4 d x} + \int{5 x d x}\right)}}$$

Apply the constant rule $$$\int c\, dx = c x$$$ with $$$c=4$$$:

$$\int{5 x d x} - {\color{red}{\int{4 d x}}} = \int{5 x d x} - {\color{red}{\left(4 x\right)}}$$

Apply the constant multiple rule $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ with $$$c=5$$$ and $$$f{\left(x \right)} = x$$$:

$$- 4 x + {\color{red}{\int{5 x d x}}} = - 4 x + {\color{red}{\left(5 \int{x d x}\right)}}$$

Apply the power rule $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$ with $$$n=1$$$:

$$- 4 x + 5 {\color{red}{\int{x d x}}}=- 4 x + 5 {\color{red}{\frac{x^{1 + 1}}{1 + 1}}}=- 4 x + 5 {\color{red}{\left(\frac{x^{2}}{2}\right)}}$$

Therefore,

$$\int{\left(5 x - 4\right)d x} = \frac{5 x^{2}}{2} - 4 x$$

Simplify:

$$\int{\left(5 x - 4\right)d x} = \frac{x \left(5 x - 8\right)}{2}$$

Add the constant of integration:

$$\int{\left(5 x - 4\right)d x} = \frac{x \left(5 x - 8\right)}{2}+C$$

$$$\int \left(5 x - 4\right)\, dx = \frac{x \left(5 x - 8\right)}{2} + C$$$A