Question

Solve the quadratic equation x2 - x = 30 by completing the square.
A. {-5, 6}
B. {-5, -6}
C. {4, 5}
D. {-4, -5}

Answer 1

BRB

Answer 2

@satellite73

Answer 3

Im not sure on how to do these still

Answer 4

x2 is x^2?

Answer 5

yes

Answer 6

(x-.5)(x-.5)+.25=30
(x-.5)^2=30-.25
(x-.5)^2=29.75
x-.5= √(29.75)
x=√(29.75)+.5
x=1/2 √(119)

Please ask to explain a step if you don't understand, I want to help you!

Answer 7

karezi-master, you can't have a radical in denominator!

Answer 8

\[x^{2}-x=30\]

Answer 9

Thats how the equation is.

Answer 10

you asked to complete the sq... Yes it is!
Do u need more explanations? Ask please if u do!

Answer 11

Don't i do \[(\frac{ -1 }{ 2} )^{2}\]

Answer 12

Ohh wait i see you use decimals

Answer 13

\[x ^{2}-x+\frac{ 1 }{ 4 }=30+\frac{ 1 }{4 }\]

Answer 14

\[\sqrt{x ^{2}}+\sqrt{\frac{ 1 }{ 4 }}=\frac{ 129 }{ 4 }\]

Answer 15

@SolomonZelman am i doing it right

Answer 16

30 + 1/4 is 121/4 not 129/4

Answer 17

You know this staff better than me! Are you a math teacher? Where do you teach?

Answer 18

ohh yeah messed up on that

Answer 19

\[x^2-x=30\]
\[x^2-x+\frac{1}{4}=30+\frac{1}{4}\]
\[(x-\frac{1}{2})^2=\frac{121}{4}\]
\[x-\frac{1}{2}=\pm \frac{11}{2}\]
\[x=\frac{11}{2}+\frac{1}{2}=\frac{12}{2}=6\]
\[x=\frac{-11}{2}+\frac{1}{2}=\frac{-10}{2}=-5\]

Answer 20

I was doing it right, but MISCALCULATED in my head!
My bad....

Answer 21

\[x ^{2}+12+20=0\]

Answer 22

\[x ^{2}+12x=20\]

Answer 23

imma try it my self see if im right

Answer 24

\[(\frac{ 12 }{ 2})^{2}=36\]

Answer 25

\[x ^{2}+12x+36=-20+36\]

Answer 26

\[\sqrt{ x ^{2}}+\sqrt{36}=\sqrt{16}\]

Answer 27

\[x +6=4\]

Answer 28

i get (2,10) @Mertsj

Answer 29

How did the 20 all of a sudden turn into -20?

Answer 30

I forgot to switch signs when i subtracted 20 to both sides

Answer 31

There are 2 square roots of 16

Answer 32

yeah +4 and -4

Answer 33

soo the other equation is 4+6 and -4+6

Answer 34

\[x^2+12x=-20\]
\[x^2+12x+36=-20+36\]
\[(x+6)^2=16\]
\[x+6=\pm4\]
\[x=4-6 or -4-6\]
\[x=-2 or x = -10\]

Answer 35

Why does the 6 go to negative?

Answer 36

@Mertsj

Answer 37

x+6=4
Can you solve that equation?

Answer 38

Ohhhh hahaha XD ok Thanks man

Answer 39

yw