Solve frac{4-sqrt{(-1)^2-4(1)(-20)}}{2(1)}=

$$\frac { 4 - \sqrt { ( - 1 ) ^ { 2 } - 4 ( 1 ) ( - 20 ) } } { 2 ( 1 ) } =$$

Evaluate

$$-\frac{5}{2}=-2.5$$

Solution Steps

Calculate -1 to the power of 2 and get 1.

$$\frac{4-\sqrt{1-4\times 1\left(-20\right)}}{2\times 1}$$

Multiply 4 and 1 to get 4.

$$\frac{4-\sqrt{1-4\left(-20\right)}}{2\times 1}$$

Multiply 4 and -20 to get -80.

$$\frac{4-\sqrt{1-\left(-80\right)}}{2\times 1}$$

The opposite of -80 is 80.

$$\frac{4-\sqrt{1+80}}{2\times 1}$$

Add 1 and 80 to get 81.

$$\frac{4-\sqrt{81}}{2\times 1}$$

Calculate the square root of 81 and get 9.

$$\frac{4-9}{2\times 1}$$

Subtract 9 from 4 to get -5.

$$\frac{-5}{2\times 1}$$

Multiply 2 and 1 to get 2.

$$\frac{-5}{2}$$

Fraction \frac{-5}{2} can be rewritten as -\frac{5}{2} by extracting the negative sign.

$$-\frac{5}{2}$$

Factor

$$-\frac{5}{2} = -2\frac{1}{2} = -2.5$$