Solve x=80^2+78^2-2*78*80cos(40)

$$x = { 80 }^{ 2 } + { 78 }^{ 2 } -2 \cdot 78 \cdot 80 \cos ( 40 )$$

Solve for x

$$x=2923.76534987515456$$

Steps for Solving Linear Equation

Evaluate trigonometric functions in the problem

$$x = {(80)} ^ {2} + {(78)} ^ {2} - 2 \cdot 78 \cdot 80 \cdot 0.766044443118978$$

Calculate 80 to the power of 2 and get 6400.

$$x=6400+78^{2}-2\times 78\times 80\times 0.766044443118978$$

Calculate 78 to the power of 2 and get 6084.

$$x=6400+6084-2\times 78\times 80\times 0.766044443118978$$

Add 6400 and 6084 to get 12484.

$$x=12484-2\times 78\times 80\times 0.766044443118978$$

Multiply 2 and 78 to get 156.

$$x=12484-156\times 80\times 0.766044443118978$$

Multiply 156 and 80 to get 12480.

$$x=12484-12480\times 0.766044443118978$$

Multiply 12480 and 0.766044443118978 to get 9560.23465012484544.

$$x=12484-9560.23465012484544$$

Subtract 9560.23465012484544 from 12484 to get 2923.76534987515456.

$$x=2923.76534987515456$$

Assign x

$$x≔2923.76534987515456$$