# Thread: need help with small word problem(sys. of linear equations)

1. ## (solved)need help with small word problem(sys. of linear equations)

two angles are supplementary. one angle is 280 degrees less than three times the other. find the measures of the angle.

my teacher gave me the answer, and i have to do the work, but im confused and dont know where to start(im bad with word probs.). thanks for any help

2. Originally Posted by NecroWinter
two angles are supplementary. one angle is 280 degrees less than three times the other. find the measures of the angle.

my teacher gave me the answer, and i have to do the work, but im confused and dont know where to start(im bad with word probs.). thanks for any help
Jhevon: the trick to word problems is to know your vocabulary. do you know what "supplementary angles" means?

Winter: Yes, they mean the angles sum to 180 degrees

Jhevon: correctomundo! so now what?

Winter: well, we know we are talking about two angles that sum to 180

Jhevon: what are the angles?

Winter: well... i don't know.

Jhevon: of course not, they are what the problem is asking you to find. so if we don't know what the values are, what do we do?

Winter: ... *lightbulb!* replace them with variables!

Jhevon: yes! very good! so call one angle x and the other y. now what can we say?

Winter: well...hmmm, um... don't look at me like that, you're making me nervous.

Jhevon: it's just me, there's no need to be nervous. think.

Winter: um, well... since one angle is 280 less than 3 times the other, i will find 3 times one angle, subtract 280 and that gives me the other angle. so i can say, 3x - 280 = y

Jhevon: brilliant idea!

Winter: but now we have a problem, Jhevon!

Jhevon: what's the problem?

Winter: well, i have one equation and two variables! I can't solve that!

Jhevon: not to worry, think. what was the first thing I asked you?

Winter: what supplementary angles mean.

Jhevon: and...?

Winter: that means the angles sum to 180.

Jhevon: and what are the angles?

Winter:...x and y?.... OH! X AND Y ADD UP TO 180!!!

Jhevon: don't shout at me!

Winter: sorry.

Jhevon: ok, so you have two equations, two unknowns

3x - 280 = y ...............(1)
x + y = 180 ................(2)

now solve that system to find the angles.

Winter: AWESOME! you're a lifesaver, Jhevon!

Jhevon: yeah, i know. anyway, have fun, i'm going to get some breakfast.