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3 votes
Value of m for which -x^2 + 8x + m =0​

1 Answer

3 votes

Answer:x=4+

16+m

x=4−

16+m

Explanation:

Question

−x

2

+8x+m=0

Solve the equation

x=4+

16+m

x=4−

16+m

Evaluate

−x

2

+8x+m=0

Multiply both sides

x

2

−8x−m=0

Substitute a=1,b=−8 and c=−m into the quadratic formula x=

2a

−b±

b

2

−4ac

x=

2

(−8)

2

−4(−m)

Simplify the expression

x=

2

64+4m

Simplify the radical expression

x=

2

8±2

16+m

Separate the equation into 2 possible cases

x=

2

8+2

16+m

x=

2

8−2

16+m

Solve the equation

x=4+

16+m

x=

2

8−2

16+m

Solution

x=4+

16+m

x=4−

16+m

Question

−x

2

+8x+m=0

Solve the equation

x=4+

16+m

x=4−

16+m

Evaluate

−x

2

+8x+m=0

Multiply both sides

x

2

−8x−m=0

Substitute a=1,b=−8 and c=−m into the quadratic formula x=

2a

−b±

b

2

−4ac

x=

2

(−8)

2

−4(−m)

Simplify the expression

x=

2

64+4m

Simplify the radical expression

x=

2

8±2

16+m

Separate the equation into 2 possible cases

x=

2

8+2

16+m

x=

2

8−2

16+m

Solve the equation

x=4+

16+m

x=

2

8−2

16+m

Solution

x=4+

16+m

x=4−

16+m

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