This is an error in the book by Master Books (ISBN: 978-0890519851) – the book with the blue cover showing the world.
The problem is discussing hens and rabbits with a total of 30 heads and 86 feet.
ERROR: The solution manual is referring to the wrong problem which is related to money.
Here is how to solve. Simultaneous equations are covered in Chapter 7. So if you forget how to solve these, refer back to chapter 7.
heads = # hens + # rabbits
feet = 2 x # hens + 4x number of rabbits
So let h be the number of hens and r be the number of rabbits.
We can re-write the above as
heads = 30 = h + r
feet = 86 = 2h + 4r
So r = 30-h
Substitute this equation into the second equation to get
86 = 2h + 4r
86 = 2h + 4(30-h) = 2h + 120 – 4h = -2h +120
Rearrange to get
2h = 120-86 = 34
h = 17 (number of hens)
Now we can find the rabbits are
R = 30-h = 30-17 = 13
Checking our work
13 + 17 = 30 (total number of heads)
2 x 17 + 4 x 13 = 86 which are the number of feet.
This is an error in the Algebra Solutions Manual
In Algebra 1, chapter 5 lesson 1 problem 10x, the answer key says the answer is true for all positive integers. But isn’t it true for all integers? 1 to the power of x =1. If it is a negative power, it is still one, right?
Dr. Callahan Answer:
You are correct. Should be for all real numbers – not just integers. I tend to test these in a calculator to make sure though 😉
So that is incorrect in the Solutions manual.
Just for completeness sake – my goto math tool is Wolfram – so here is there answer.
The test in the Teacher Guide for Test 2B on page 211 has an incorrect answer. The answer given in the solution manual is y=4x+1.
The correct answer is y = 4x-3.
Thanks Marybeth for catching this.
Angela’s son brought this error in the Earth cover Algebra I Solutions Manual to our attention. Thank you!
The problem (Ch3.4 #9) wording changed completely from the salamander cover to the Earth cover. However, the solution in the old and new solutions manuals is the same. In other words, both manuals have the solution to the salamander wording of the problem. The Earth solutions manual has the wrong solution to the Earth Ch3.4 #9 problem.
Angela’s son worked it perfectly and here is his correct solution to the Earth cover Algebra I Chapter 3.4 Set 1 #9 problem.
A question brought to us by Marybeth. Thank you!
In Jacob’s Elementary Algebra Chapter 1 Review Set I Question 14b page 51.
“What is the total number of atoms in x propane molecules as a sum?”
The Solutions Manual for Elementary Algebra on page 14 lists the answer as:
b) 3x + 5x
The “5” is a typo. The answer should be 3x + 8x.
3x carbon atoms plus 8x hydrogen atoms
Test shows: 3(x+1)^1/2=(x+7)^1/2 while the answer booklet shows: 3(x+1)^1/2=(x-7)^1/2.
The answer key is correct. For the test, please change the problem to 3(x+1)^1/2=(x-7)^1/2
I believe I found an error in the answer key in the 5th Ed. Algebra 1 Teachers Guide. On Test 4, #9.d., the answer in the key (p. 88) should be (x – y squared)squared, shouldn’t it, rather than (x + y squared) squared?
Dr. Callahan answered:
You are correct. Thanks for pointing it out. The final answer should be
The correct answer should have a minus sign and be
(x^3 – y^3)^2
The teacher guide and tests have some corrections to be found here!
Algebra 1 Test 1 Errors & Notes
Algebra 1 Test 2 Error Log
Algebra Test 6 Number 7
Algebra Test 5
Chapter 9 lesson 6 problem 16 f -The book is fine –but the Solutions Manual has a minus sign instead of a + sign.