# pre-calc numbers problem-urgent help!

• Apr 19th 2009, 11:01 AM
tmac11522
pre-calc numbers problem-urgent help!
The sum of two numbers is twice their difference. The larger number is 7 more than twice the smaller. Find the numbers.
• Apr 19th 2009, 11:12 AM
e^(i*pi)
Quote:

Originally Posted by tmac11522
The sum of two numbers is twice their difference. The larger number is 7 more than twice the smaller. Find the numbers.

Let the numbers be a and b

\$\displaystyle a+b = 2(a-b)\$ (eq1)

\$\displaystyle b-2a = 7\$ (eq2)

From this you can solve it simultaneously
• Apr 19th 2009, 11:18 AM
rubix
Quote:

Originally Posted by tmac11522
The sum of two numbers is twice their difference. The larger number is 7 more than twice the smaller. Find the numbers.

let x and y be two required numbers. Let x be the larger number in concern.

1) the sum of two numbers is twice their difference

\$\displaystyle x+y = 2 (x-y) \$

2) the larger number is 7 more than twice the smaller.

\$\displaystyle x = 2y + 7 \$

you now have two equations and two unknown. Use substitution to solve.

P.S. this is wrong section. If this is a pre-calc problem you should have posted it in pre-calc section.