MATH! HELP! Parenthesis counting! example: 2(a+b) -(a+b)= ?

Question

1. 2(a+b) -(a+b)= ?
2. 2-(-a - b + c) + 7 - 2(c+a-b)
3. (a+b) + (a-b)
4. (a+b) (a+b)
5. (a-b) (a-b)
6. a/2 + 5( a/5 - 3/5)

when i write a/2 meaning a divided by 2

7. 3(a/3 + b/2)

8. -7( -b/7 - 5a/2 + 8/3)

9. -4(a+3b) + 2( b/4 - 2a/5) - 7b

i just have to understand how to do it. i missed a lesson and my teacher sucks. but if you give answers too it would be great so i can compare. :) thanks

Answer 1

just distrubute the number/operation sign before the paranthesis to each number in the parenthesis.

1. 2(a+b) -(a+b)= 2a+2b-a-b=a+b (distribute the 2 to a and b and distribute the negative sign to a and b( think of the negative sign to read -1))

2. 2-(-a - b + c) + 7 - 2(c+a-b)=2+a+b-c+7-2c-2a+2b=

-a+3b-3c+9

3. you can drop the paranthesis in this problem.

(a+b) + (a-b)=a+b+a-b=2a

4. (a+b) (a+b)=(a+b) squared=a squared+2ab+b squared (this is a formula and u should memorize it.)

5. (a-b) (a-b)=(a-b) squared= a squared- 2ab+b squared. (this is another formula. the only difference if the minus sign.)

6.a/2 + 5( a/5 - 3/5)=1/2 X a+a-3= 3/2a-3 (a/2 is equal to one half a. when u distribute the five, it cancels out with the 5's on the bottom and leaves the numerator.

7. 3(a/3 + b/2)=a+3b/2 (distribute the 3 to the fraction)

8. -7( -b/7 - 5a/2 + 8/3)=b+35a/2-56/3 (be careful of the negative. minus and minus = plus. minus and plus=minus

9. -4(a+3b) + 2( b/4 - 2a/5) - 7b=-4a-12b+b/2-4a/5. (i left it in an unsimplified form but you get the point. distribute the-4 and 2 to all numbers in the paranthesis. and than add like terms)



hope this helped

Answer 2

this looks like distributing to me. THe trick is to remember that -(a+b) means -1*(a+b}



1. 2a+2b -a -b = a+b

2. 2+a+b-c+7-2c-2a+2b = -a+3b-3c+9



basically, each time you have a negative outside the parentheses, you change the sign of each term in parentheses. Good luck!

Answer 3

What do you want to know? When you write 2(a+b)...=? We need to either know the variables or the solution, but other than that, all we can do is simplify #1 into 2(a+b)-(a+b)=2a+2b-a+b ...

Answer 4

1) 2(a+b)-(a-b)

=2a+2b-a-b

=2a-a+2b-b

=a+b

2) 2-(-a-b+c)+7 -2(c+a-b)

= 2+a+b-c+7-2c-2a+2b

=2+7+a-2a+b+2b-c-2c

=9-a+3b-3c

3) (a+b)+ (a-b)

=a+b+a-b

=a+a+b-b

=2a

4)(a+b) (a+b)

=a squared+b squared

=square root a squared+b squared

=a+b

5)(a-b) (a-b)

=a squared+b squared

=square root a squared+b squared

=a+b

6)a/2 +5(a/5-3/5)

=a/2+a-3

=a/2 x a squared/2-3

=2a squared/2 -3

=a squared - 3

square root a squared - 3

=a-3

7)3(a/3+b/2)

=3 x a/3 + 3b/2

=a+3b/2

8)-7(-b/7-5a/2+8/3)

=-7 -b/7-35a/2 +28

=b-35a/2+28

9)-4(a+3b) + 2(b/4-2a/5) -7b

=-4a-12b+b/2-4a-7b

=-4a-4a/5-12b+b/2-7b

=-20a/5-4a/5-24b/2+b/2-14b/2

=-24a/5-38b/2

=-24a/5-19b



yay!! done!!!

Answer 5

1. (2 - 1)(a + b) = a + b

2.

3. 2a

4. a^2 + 2ab + b^2

5. a^2 - 2ab + b^2

6. a/2 + a - 3 = (3 / 2)a - 3

7. a + (3b / 2)