Question

Select the correct answer.
Find the solution(s) for x in the equation below.

Answer 1

B(x=4,x=5)

Explanation:

Here,

`x^(2) -9x+20=0`

We can find the value of x by various methods.

Method 1

By using formula

x=-b±√b²-4ac/2a

For ax²+bx+c=0

Here,

a=1, b=9, c=20

Putting the values.

x=-b±√b²-4ac/2a

x=-(-9)±√9²-4×1×20/2×1

Taking positive one.

`x=(-(-9)+ √(81-80) )/(2) \\\\x=(9+1)/(2) \\\\x=5`

Taking negative one.

`x=(-(-9)- √(81-80) )/(2) \\\\x=(9-1)/(2) \\\\x=4`

x=5,x=4

Method 2

`\hookrightarrow x^(2) -9x+20=0\\\\\hookrightarrow x^(2)-4x-5x+20=0\\\\\hookrightarrow x(x-4)-5(x-4)=0\\\\\hookrightarrow (x-5)(x-4)=0`

x-5=0....I

x-4=0.....II

Solving equation I

x-5=0

x=5

Solving equation II

x-4=0

x=4

Answer 2

• x²-9x+20=0
• x²-5x-4x+20=0
• x(x-5)-4(x-5)=0
• (x-4)(x-5)=0

So

• x=4 and x=5

Option B