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What is the value of k? with a= 4 and b= -7​

What is the value of k? with a= 4 and b= -7​-example-1

2 Answers

4 votes

Answer:

k= -7/4

Step-by-step explanation:

y=ax^2+3x+b, a=4 b=-7

y=4x^2+3x-7

where y=0 at the intersection

4x^2+3x-7=0

by using factorisation method

product=-28

sum=3

factors=7,-4

(4x^2-4x)+(7x-7)=0

4x(x-1)+7(x-1)=0

(4x+7)(x-1)=0

4x+7=0, x-1=0

x=-7/4, x=1

therefore, k= -7/4

User MDIT
by
8.3k points
4 votes

Answer:

The value of k
-(121)/(16)

Step-by-step explanation:

⟺ Substitute a = 4 and b = -7 in the equation.

From
y=ax^2+3x+b

Our new equation is
y=4x^2+3x-7

⟺ Use the formula of finding k value.


k=(4ac-b^2)/(4a)\\

⟺ Substitute a = 4 b = 3 and c = -7 in the formula. (Arranged Expression)


k=(4(4)(-7)-(3)^2)/(4(4))\\k=(-112-9)/(16)\\k=-(121)/(16)\\

If you are curious where k-value/term comes form, it comes from this equation.


y=a(x-h)^2+k

User Loliki
by
8.4k points

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