Jason bought 7 new baseball trading cards to add to his collection. The next day half of his collection. There are now only 30 cards left.

8 cards

Step-by-step explanation:

Work Backwards:

30/2 is 15

15-7 is 8.

Hope this helps :D

Step-by-step explanation:

Let x be the number of cards Jason had initially in his collection.

"Jason bought 9 new baseball trading cards to add to his collection"

x

+

9

is the equation because  

x

is the initial number of cards he has and he bought another 9

"His dog ate half of his collection"

1

2

(

x

+

9

)

because  

x

+

9

is what he had before his dog ate his cards and since his dog ate half, there is a  

1

2

added to the equation

"42 cards left"

1

2

(

x

+

9

)

=

42

Since his dog ate half, he is left with half of his initial card collection.

x

+

9

=

42

×

2

x

+

9

=

84

x

=

84

−

9

x

=

75

-3

step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3

step-by-step explanation:

; fx