$$9x^2-30x^2-25$$

$$\left(2-9\right)+\left|5-\left(8+2\right)\right|$$

$$-12+5\left(-3\right)^2$$

$$\int503.5e^{-0.01x^2}dx$$

$$\left(1+3x^2\right)^{\frac{1}{2}}\left(1+3x^2\right)^{\frac{1}{2}}$$

$$42+42+42+42$$

$$0.68-0.24$$