Solve 49=81+x^2-2*9xcos(28.6)

$$49 = 81+ { x }^{ 2 } -2 \cdot 9x \cos ( 28.6 )$$

Solve for x_0

$$x_{0}=\frac{1000000000000000x^{2}+32000000000000000}{15803693557703649}$$

Steps for Solving Linear Equation

Evaluate trigonometric functions in the problem

$$49 = 81 + {(x)} ^ {2} - 2 \cdot 9 x 0.8779829754279805$$

Multiply 2 and 9 to get 18.

$$49=81+x^{2}-18x_{0}\times 0.8779829754279805$$

Multiply 18 and 0.8779829754279805 to get 15.803693557703649.

$$49=81+x^{2}-15.803693557703649x_{0}$$

Swap sides so that all variable terms are on the left hand side.

$$81+x^{2}-15.803693557703649x_{0}=49$$

Subtract 81 from both sides.

$$x^{2}-15.803693557703649x_{0}=49-81$$

Subtract 81 from 49 to get -32.

$$x^{2}-15.803693557703649x_{0}=-32$$

Subtract x^{2} from both sides.

$$-15.803693557703649x_{0}=-32-x^{2}$$

The equation is in standard form.

$$-15.803693557703649x_{0}=-x^{2}-32$$

Divide both sides of the equation by -15.803693557703649, which is the same as multiplying both sides by the reciprocal of the fraction.

$$\frac{-15.803693557703649x_{0}}{-15.803693557703649}=\frac{-x^{2}-32}{-15.803693557703649}$$

Dividing by -15.803693557703649 undoes the multiplication by -15.803693557703649.

$$x_{0}=\frac{-x^{2}-32}{-15.803693557703649}$$

Divide -32-x^{2} by -15.803693557703649 by multiplying -32-x^{2} by the reciprocal of -15.803693557703649.

$$x_{0}=\frac{1000000000000000x^{2}+32000000000000000}{15803693557703649}$$

Solve for x (complex solution)

$$x=-\sqrt{\frac{15803693557703649x_{0}}{1000000000000000}-32}$$

$$x=\sqrt{\frac{15803693557703649x_{0}}{1000000000000000}-32}$$

Solve for x

$$x=\frac{\sqrt{\frac{15803693557703649x_{0}}{250000000000000}-128}}{2}$$

$$x=-\frac{\sqrt{\frac{15803693557703649x_{0}}{250000000000000}-128}}{2}\text{, }x_{0}\geq \frac{32000000000000000}{15803693557703649}$$