AlgebraGuru

I don't think you can delete a post.

thank you soo much!!!

Let's find the slope of each line

y = 9x - 3         y = -8 + 8

And the slope of the first line is 9

And the slope of the second line is -8

And taking the tangent inverse of the second line, we have

tan-1(-8)  = -82.87°   We need to add 180° to this to get the correct angle = 97.13°

And taking the tangent inverse of the first line, we have

tan-1(9) = 83.66°

So.....subtrating the second result from the first, we have 13.47° = about 13°

Thanks!!

It's 2013, I just went to Melody's profile and went to the first answer.

It think 2013 or 2014. But, it's just a guess.

Correct option is 30

a,b are roots of x2−2cx−5d=0
⇒a+b=2c

and c,d are roots of x2−2ax−5b=0 
⇒c+d=2a
 

∴(a−c)+(b−d)=2(c−a)

⇒(b−d)=3(c−a)…(1)   
Since c is the root of x2−2ax−5b=0⇒c2−2ac−5b=0…(2)

Similarly a is root of x2−2cx−5d=0⇒a2−2ac−5d=0…(3)

On subtracting (3) from (2)
c2−a2=5(b−d)

⇒(c−a)(c+a)=5×3(c−a)……(from(1))
⇒c+a=15

∴a+b+c+d=2c+2a

=2(c+a)=2×15=30

1/2 * 8 * 4 = 16 units^2

Thank you soooooo much!!!!!! I can't thank you enough!!

Also, I forgot to metion

Two right triangles, ABC and ACD, are joined as shown. Squares are drawn on four of the sides. The areas of three of the squares are 9, 16 and 36 square units. What is the number of square units in the area of the fourth square?

Note that the diagram is not drawn to scale.