Question

Solve and check. Label any contradictions or identities. what did i do wrong?
– 8a/7 – 2 = 4

-8a/7*7/8=4+2
a=6
Check:
8*6/7= 4
48/7=4
6 6/7-2 =4
4 6/7= 4
Thus -8a/7-2=4 is in fact an Contradication.

Answer 1

no, you did it incorrectly.
-8a/7 = 6
now multiply both sides by 7/8
you forgot to multiply on the RHS

Answer 2

OK i didn't multiple the other side that's why is wrong

Answer 3

thats right

Answer 4

8a/7= 6
8/7a / 7/8 = 6/1 * 8/6
a = 48/6
a=8
Thus -8a/7-2=4 is in fact an Contradication.

Answer 5

why are you multiplying the right hand side by 8/6?

Answer 6

sorry made a mistake. i meant this
8a/7= 6
8/7a / 7/8 = 6/1 * 7/8
a = 36/8
a= 4 1/2
Thus -8a/7-2=4 is in fact an Contradication.

Answer 7

6 times 7 is 42. Please do your calculations properly.

Answer 8

you are correct i should of used the calculator. thanks for the correction

Answer 9

so the answer is 5.25 Or 5 1/4

Answer 10

if you are solving an equation, you cannot get a contradiction, because when you solve an equation for a variable, that variable is what solves the equation. In other words, that variable is the missing link.

Answer 11

So its is an identiy. this is what i need to answer weather it's an label of any contradictions or identities?

Answer 12

But it's not equal to? I thought when u solve the equation and one side is not equal to the other side then that's an contradiction?

Answer 13

OK understood.

Answer 14

no, when you solve an equation, you are finding out the value that "solves the equation".
for example,
x +3 = 5
subtract 3 from both sides
x = 2
I solved the equation x+3 = 5
and got x to be the value 2
that means this value of x cannot contradict the equation because I solved the equation to get the value of x as 2.

Answer 15

the very fact that I solved the equation means that the value I got as the missing link cannot be a contradiction. do you get it?

Answer 16

I understand that but when i found the answer for a in my problem it didn't equal 4 which is what it was suppose to do. I don't know how to get it to equal to 4 without changing the entire problem

Answer 17

if you solve correctly, the value you find for a will ALWAYS solve the problem. It just means you made some error in calculating the value.

Answer 18

-8a/7 - 2 = 4
add 2 to both sides
-8a/7 = 6
a = -42/8
a = -5.25
now, substitute -5.25 in the original equation
-8(-5.25)/7 - 2 = 4
LHS = -8(-5.25)/7 -2 = 42/7 -2 = 6-2 = 4 = RHS

Answer 19

exactly and i believe it's in what i am multiplying. i have to be more careful when I'm typing the numbers because that where my error are coming from. thanks so much for the help.

Answer 20

no problem.

Answer 21

make sure you do the calculations correctly.