# algebra

solving the equation (x+4)(x-4)=9 Eric stated that the solution would be x+4=9>x=5 or (x-4)=9=>x=13
However one of these solution fails to work when subsituted back to the original equation. Why?olve and explain the reasoning. Can someone please help me?

1. 👍 0
2. 👎 0
3. 👁 120

## Similar Questions

1. ### Algebra

Create a system of equations that includes one linear equation and one quadratic equation. Part 1. Show all work to solving your system of equations algebraically. Part 2. Graph your system of equations, and show the solution

Solve each equation by graphing the related function. If the equation has no real-number solution, write no solution. NOTE: when I write + it has a minus on the bottom too x^2+7=0 a. x= +7 b. x = +3.5 c. x= 0 d. no solution ***

3. ### Algebra 1 check answers

If you were solving a system of equations and you came to a statement like 1 = 3, what do you know about the solution to the system? The solution is (1, 3). The solution is x = 1 and y = 3. There is no solution. There are

4. ### Algebra

A chemist mixed a 70% alcohol solution with a 30% alcohol solution to make a 45% alcohol solution. How many liters of each were used to make 120 L of a 45% solution? I tried solving this with elimination method and made two

1. ### Algebra 1

the sum of eric's and bob's weights is 9 times greater than the difference of their weights. the positive difference of their weights is also 240 lbs less than the sum. if eric weighs less than bob, find bob's weight. i can't find

2. ### calculus

is y = x^3 a solution to the differential equation xy'-3y=0?? how do i go about solving this??? also, is there a trick to understanding differential equations? i'm really struggling with this idea, but i'm too embarassed to ask my

3. ### Math 7 - NYS Math Exam Review Help! (Q2)

9. Eric's mother wants to help him with his math homework. She puts 24 cookies in a cookie jar. Twelve (12) of the cookies are chocolate chip, 8 are oatmeal, and 4 are peanut butter. She then has Eric select a cookie from the jar

4. ### Math

Eric had 13 tiles to arrange in a rectangular design. He drew a model of the rectangles he could make with the 13 tiles? How does Eric's drawing show that 13 is a prime number?

1. ### Algebra

Please help to find x, y 1. 8x-y=17 6x+y=11 2. 5x-2y=17 2x+3y=3 Question no.1 8x-y=17 6x+y=11 (adding the equation) __________ (-y and +y will be 0) 14x =28 Taking variables to one side x=28 __ 14 14*2=28 therefore x=2 substitute

2. ### Algebra

Here asking for more help! -- Connexus, Lesson 3: Solving Quadratic Equations -- 1. What is the solution of n^2-49=0 [] -7 [] 7 [+] +7 [] No solution 2. What is the solution of x^2+64=0? [] -5 [+] 8 [] +8 [] No solution What is

3. ### 2 STEP MATH EQUATIONS

eric has a dog walking business. He charges \$13per dog he walks and \$6 for the water he buys for the dogs. If he made \$97 on Monday, write an equation to find the number of dogs he walked on Monday. I got an answer of 7 dogs on

4. ### Algebra

The sum of Eric and Bob's weights is 9 times greater than the difference of their weights. The positive difference of their weights is also 240 pounds less than the sum. If Eric weighs less than Bob, find Bob's weight. I am not