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pav-90 [236]
3 years ago
15

2x² + 9 = - 7x how do i find an answer using the quadratic formula

Mathematics
1 answer:
jok3333 [9.3K]3 years ago
7 0

Answer:

(-7 ± i√(-23)) / 4

Step-by-step explanation:

Unless you have to show your work, you don't really have to use the quadratic formula unless it is unfactorable.

2x² + 9 = -7x    (Add 7x to both sides)

2x² + 7x + 9 = 0    ( The quadratic formula is (-b ± √(b^2 - 4ac))/2a )

A = 2

B = 7

C = 9

(-7 ± √(49 - 72))/4

= (-7 ± √(-23))/4    (Which simplifies to an imaginary answer, proving that this is, indeed, unfactorable)

= (-7 ± i√(-23))/4

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Answer is B how words are arranged in a sentence
4 0
3 years ago
Two classroom have a total of 45 people in them. the first class is a math class with 5 more students than the science class. Ho
german

Answer:

x=25

Step-by-step explanation:

Set an equation:

x + x -5 = 45

Combine like terms:

2x - 5 = 45

Add 5 to both sides:

2x = 50

Divide both sides by 2:

\frac{2x}{2} = \frac{50}{2}

x = 25

6 0
3 years ago
What are the exact values of sin(2π3radians) and cos(2π3radians)
topjm [15]
We know that
2π/3 radians-------> convert to degrees-----> 2*180/3---> 120°
120°=90°+30°

Part a) Find <span>sin(2π/3)
</span>sin(2π/3)=sin (90°+30°)
we know that
sin (A+B)=sin A*cos B+cos A*sin B
so
sin (90°+30°)=sin 90*cos 30+cos 90*sin 30
sin 90=1
cos 30=√3/2
cos 90=0
sin 30=1/2
sin (90°+30°)=1*√3/2+0*1/2-----> √3/2

the answer part a) is
sin(2π/3)=√3/2

Part b) Find cos (2π/3)
cos (2π/3)=cos (90°+30°)
we know that
cos (A+B)=cos A*cos B-sin A*sin B
so
cos (90°+30°)=cos 90*cos 30-sin 90*sin 30
sin 90=1
cos 30=√3/2
cos 90=0
sin 30=1/2
cos (90°+30°)=0*√3/2-1*1/2----> -1/2

the answer part b) is
cos (2π/3)=-1/2


4 0
3 years ago
Please help me with this im not good in math i have no brain
Tanzania [10]
The answer is the first one. I am pretty sure.
4 0
3 years ago
Please help me I really need it
notsponge [240]

Answer:

a) what is the five

Step-by-step explanation:

just read and finde the answer to win points

3 0
3 years ago
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