Download presentation

Presentation is loading. Please wait.

Published byEric Leeds Modified over 4 years ago

1
Example 2. The length of a rectangle is 7 more than the width. Its area is 30. Find the dimensions of the rectangle. x x + 7 A = 30 A = lw 30 = x(x + 7) 30 = x 2 + 7x -30 -30 0 = x 2 + 7x – 30 0 = ( )( ) Use the x-box to factor the trinomial if you can’t do it in your head. x + 10 x – 3 0 = x + 10 -10 -10 = x x – 3 = 0 +3 +3 x = 3 Reject -10 because you cannot have a negative dimension. reject Answer: Length = 3 + 7 = 10 Width = 3

2
Example 3. Kara has two sisters. One of the sisters is 7 years older than Kara. The other sister is 3 years younger than Kara. The product of Kara's sisters' ages is 24. How old is Kara? (Hint: let x = Kara’s age, and use the sentence in the problem to write an equation to solve.) Let: x = Kara’s age x – 3 = youngest sister’s age x + 7 = oldest sister’s age (x – 3)(x + 7) = 24 x 2 + 7x – 3x – 21 = 24 x 2 + 4x – 21 = 24 -24 -24 x 2 + 4x – 45 = 0( )( ) = 0 x + 9 x – 5 x + 9 = 0 -9 -9 x = - 9 x – 5 = 0 +5 +5 x = 5 reject Answer: Kara is 5

3
1)Let x = a number x 2 + 8 = 6x -6x -6x x 2 – 6x + 8 = 0 Put into standard form: ax 2 + bx + c then factor. 2)Let x = a number x 2 – 15 = 2x -2x -2x x 2 – 2x – 15 = 0 Put into standard form: ax 2 + bx + c then factor. 3) Let x = a number 2x 2 + x = 6 -6 -6 2x 2 + x – 6 = 0 4)Let x = a number 4x 2 – 7 = 18 -18 -18 4x 2 – 25 = 0 5) Let x =1 st CI x + 1 = 2 nd CI x(x + 1) = 56 x 2 + x = 56 -56 -56 x 2 + x – 56 = 0

Similar presentations

Presentation is loading. Please wait....

OK

3.6 Equations and Problem Solving

3.6 Equations and Problem Solving

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google