I need help figuring out the formulas to solve these 2 word problems:
1. The sum of 2 numbers is 8.5, and their product is 18. Find the numbers.
2. Two positive numbers differ by 5, and their squares differ by 96. Find the nuimbers.
Thanks in advance for any help in finding which formulas to use to solve these.
2006-07-20 18:53:47 · 9 answers · asked by mireski5 2 in Education & Reference ➔ Homework Help
Thanks to all who were kind enough to answer with out the sarcastic replies. I had already tried the formuals given before I asked the questions, but was getting some crazy answers. I thought maybe I was trying to use the wrong ones. Thanks anyway...
2006-07-20 19:23:02 · update #1
x + y = 8.5
x * y = 18
x - y = 5
x² + y² = 96
2006-07-21 00:01:46 · answer #1 · answered by SAMUEL D 7 · 1⤊ 1⤋
1. The sum of 2 numbers is 8.5, and their product is 18. Find the numbers.
Let the two numbers be x and y,
x+y=8.5
x*y=18
2. Two positive numbers differ by 5, and their squares differ by 96. Find the nuimbers.
let the two numbers be x and x-5,
x^2 - (x-5)^2=96
2006-07-21 08:30:09 · answer #2 · answered by R@inY 3 · 0⤊ 0⤋
For the following explanation
"=>" means "implies"
"^" means "power"
1.
Given: x + y = 8.5 => y = 8.5 - x
x*y = 18, Substitute b in this equation.
x * (8.5-x) = 18 => 8.5x - x^2 = 18 => x^2 -8.5x + 18 = 0.
For the above obtained eqaution u can use the formula
(-b +/- (b^2 - 4ac)) / 2a...
In this problem a=1, b=-8.5 c=18....
So the result, the numbers are .. 4.75 and 3.75.
I hope u can solve the other problem in the similar way.
2006-07-21 03:02:37 · answer #3 · answered by Chitra 1 · 0⤊ 0⤋
there are two approaches to this problem
solve either of these formulas for y then use your solution
for a y value in the other formula
x*y=18
x+y=8.5
for one instance:
x*y=18
y=(18/x)
so
x+(18/x)=8.5
now solve for x
then after you find x y=8.5-x
the second one:
in this case y is the lower value
x-y=5
sqr(x)-sqr(y)=96
x=y+5
sqr(y+5)-sqr(y)=96
when you find y use it to solve for x
for this question it looks tricky
7*7=49
12*12=144
the difference is 95 for the numbers 7 and 12
thus the number you seek is slightly above these numbers
2006-07-21 02:20:38 · answer #4 · answered by mickyyyyy 3 · 0⤊ 0⤋
You have to write the equation to solve for the numbers based on the information provided. For example, the first problem would be...
X + Y = 8.5
X * Y = 18
You would solve for X or Y and use that to plug into the equation to solve for the other one.
You follow the same procedure for the next problem.
2006-07-21 01:58:53 · answer #5 · answered by jd 6 · 0⤊ 0⤋
1. x+y =8.5
xy=18
2.2x-2y=5
x^2-x^2=96
2006-07-21 02:00:13 · answer #6 · answered by judy 3 · 0⤊ 0⤋
1: x+y= 8.5
xy=18
substitute.
2; |x-y|=5
|x^2-y^2|=96
again, substitution.
Wow, it's been so long since I've done 7th grade math. I almost miss it.
2006-07-21 02:00:27 · answer #7 · answered by Jim T 6 · 0⤊ 0⤋
I hate maths
2006-07-21 01:58:19 · answer #8 · answered by ethio 2 · 0⤊ 0⤋
Do your own homework.
2006-07-21 02:17:57 · answer #9 · answered by Mike42884 2 · 0⤊ 0⤋