It is just excellent that you tried. Now please show us your work so that we can show you where you went wrong and to also have an idea as to what method you already know.If 6a+6b=30 and 3a+2b=14 what is the value of b?
How should I solve this by combination? I tried but I can't get it.
I am not sure what you mean by So a=5-6\5b, but whatever you do mean it is wrong (sorry).What i did was try 'n use combination. So 6a+6b=30
I isolated a the variable a to get its value. So 6a=30-6b
Then I divided the term by 6 on both sides. So a=5-6\5b
After that I didn't know what to do whether i should of added it to the value of a or kept simplifying it by dividing 6 and 5.
Okay; that's not "combination" (also known as "elimination" or "addition"); that's substitution. Instead, try combining the two equations:What i did was try 'n use combination. So 6a+6b=30
I isolated a the variable a to get its value. So 6a=30-6b
Then I divided the term by 6 on both sides. So a=5-6\5b
After that I didn't know what to do whether i should of added it to the value of a or kept simplifying it by dividing 6 and 5.
When I multiplied by negative two and eliminated the a value I got 2b=2.Okay; that's not "combination" (also known as "elimination" or "addition"); that's substitution. Instead, try combining the two equations:
. . . . .6a + 6b = 30
. . . . .3a + 2b = 14
If the second equation is multiplied by -3, then the b-terms would cancel out when the equations are combined by adding down. But if the second equation were multiplied by -2, then the a-terms would cancel out, plus I'd be dealing with smaller numbers. So let's multiply the second line by -2:
. . . . .+6a + 6b = +30
. . . . .-6a - 4b = -28
Add down, etc, etc.
What i did was try 'n use combination. So 6a+6b=30
I isolated a the variable a to get its value. So 6a=30-6b
Then I divided the term by 6 on both sides. So a=5-6\5b
I think you accidently used "5" in one of those divisions: a= 30/6- (6b)/6= 5- b.
Putting that back into the second equation, 3a+ 2b= 3(5- b)+ 2b= 15- 3b+ 2b= 15- b= 14 so b= 15- 14= 1.After that I didn't know what to do whether i should of added it to the value of a or kept simplifying it by dividing 6 and 5.
Except that the instructions clearly said to use "combination", not substitution.Divide 1st equation by 6: a + b = 5
So a = 5 - b
Substitute in 2nd equation...
No, no! The problem asked you to solve for b. Since you know b=1 you are done. There is no need to solve for a.When I multiplied by negative two and eliminated the a value I got 2b=2.
I believe that further down you divide by two and and get b equals 1.
Then plug in for b and get the correct answer.