Question

twice the sum of a number and seven is eight find the number

Answer 1

then solve

Answer 2

\[2(x+7)=8\]?

Answer 3

if so, divide both sides by 2, then subtract 7 from both sides to get your answer

Answer 4

steps clear?

Answer 5

-1

Answer 6

?

Answer 7

nope

Answer 8

first divide by 2 to get
\[x+7=8\div 2\] or
\[x+7=4\]

Answer 9

then subtract 7 from both sides

Answer 10

theres 3 sides 2,7,8 both sides meaning?

Answer 11

i mean "both sides of the equal sign"

Answer 12

so u add 7 and 2?

Answer 13

for example if i had
\[x+3=-2\] i would say "subtract 3 from both sides" giving
\[x+3-3=-2-3\]
\[x=-5\]

Answer 14

hold the phone

Answer 15

we start with
\[2(x+7)=8\] yes

Answer 16

this means just what the problem asked "multiply 2 times a number plus 7"

Answer 17

you do not know what that number is yet, that is the variable x

Answer 18

but the parentheses means multiplication. you can multiply 2 times x and 2 times 7 if you like

Answer 19

the "distributive property" says that
\[2(x+7)=2\times x + 2\times 7=2x+14\]

Answer 20

ok

Answer 21

so if you like you can change
\[2(x+7)\] into
\[2x+14\]

Answer 22

and now you have the equation
\[2x+14=8\]

Answer 23

ok

Answer 24

you want x by itself. we proceed with the following steps:
1) subtract 14 from both sides of the equal sign

Answer 25

clear what i mean by "from both sides"?

Answer 26

clear what u mean ? do i mean Do I know what to clear huh????

Answer 27

no i mean "do you understand what i mean when i say subtract 14 from both sides?"

Answer 28

yes , but from the 2x and 14 right?

Answer 29

your job is to get x by itself. at the moment you have
\[2x+14\] so you have to get rid of that 14 by subraction

Answer 30

i will write the steps. start with
\[2x+14=8\] then subtract 14 from both sides to get
\[2x+14-14=8-14\]
\[2x=-6\]

Answer 31

now we got rid of the annoying 14

Answer 32

but we are not done because we want x by itself and we have
\[2x\] so to get x by itself you have to divide both side (of the equal sign) by 2

Answer 33

ok

Answer 34

so we divide as follows
\[\frac{2x}{2}=\frac{-6}{2}\]
\[x=-3\]

Answer 35

hope that made it a little clearer but maybe not so i write out one real quick. solve
\[2(x-4)=10\]
\[2x-8=10\]
\[2x-8+8=10+8\]
\[2x=18\]
\[\frac{2x}{2}=\frac{18}{2}\]
\[x=9\]

Answer 36

need another one?

Answer 37

thank you. three times the difference of a number and seven is one less than twice the number find the number

Answer 38

Roseanne - from both sides means from both sides of the equal sign