# This doesn't make sense..

• January 23rd 2008, 12:36 PM
eh501
This doesn't make sense..
The measures of two complementary angles are represented by (3x+15) and (2x-10). What is the value of x.

I got 19, but when i sub it in for x, it doesnt add up to 90. What am i doing wrong?
• January 23rd 2008, 12:46 PM
Soroban
Hello, eh501!

Quote:

The measures of two complementary angles are represented by (3x+15) and (2x-10).
What is the value of x?

I got 19, but when i sub it in for x, it doesnt add up to 90.
What am i doing wrong?

You're checking your answers . . . Good for you!

You made a small slip in arithmetic . . .

$(3x+15) + (2x- 10)\:=\:90\quad\Rightarrow\quad 5x + 5 \:=\:90\quad\Rightarrow\quad 5x \:=\:85\quad\Rightarrow\quad x \:=\:17$

• January 23rd 2008, 12:51 PM
eh501
Ahhh man, now i know what i did wrong. I didn't -5 instead i +5.