Solve 12.6^2=6.6^2+7.2^2-2*6.6*7.2*x

$${ 12.6 }^{ 2 } = { 6.6 }^{ 2 } + { 7.2 }^{ 2 } -2 \cdot 6.6 \cdot 7.2 \times x$$

Solve for x

$$x=-\frac{2}{3}\approx -0.666666667$$

Steps for Solving Linear Equation

Calculate 12.6 to the power of 2 and get 158.76.

$$158.76=6.6^{2}+7.2^{2}-2\times 6.6\times 7.2x$$

Calculate 6.6 to the power of 2 and get 43.56.

$$158.76=43.56+7.2^{2}-2\times 6.6\times 7.2x$$

Calculate 7.2 to the power of 2 and get 51.84.

$$158.76=43.56+51.84-2\times 6.6\times 7.2x$$

Add 43.56 and 51.84 to get 95.4.

$$158.76=95.4-2\times 6.6\times 7.2x$$

Multiply 2 and 6.6 to get 13.2.

$$158.76=95.4-13.2\times 7.2x$$

Multiply 13.2 and 7.2 to get 95.04.

$$158.76=95.4-95.04x$$

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

$$95.4-95.04x=158.76$$

Subtract 95.4 from both sides.

$$-95.04x=158.76-95.4$$

Subtract 95.4 from 158.76 to get 63.36.

$$-95.04x=63.36$$

Divide both sides by -95.04.

$$x=\frac{63.36}{-95.04}$$

Expand \frac{63.36}{-95.04} by multiplying both numerator and the denominator by 100.

$$x=\frac{6336}{-9504}$$

Reduce the fraction \frac{6336}{-9504} to lowest terms by extracting and canceling out 3168.

$$x=-\frac{2}{3}$$