Today in Math class, Mr. Harbeck showed us how to turn an algebraic problem solving into an algebraic equation and then answer it. I have chosen the last 3 algebraic problem solving from page 45 on the purple booklet, because a some people were having trouble answering them.

Here is my first example from page 45, letter C.

C. Three desks and a bookcase together weigh 157 lb. The bookcase weighs 34 lb. How much does each desk weigh?

First you have to write a simple sentence like: Each desk weigh ____.

To complete this sentence, you have to figure out the equation for this problem solving, and answer it then verify to see if it's correct.

3x + 34=157

3x + 34=157-34

3x= 123

3x/3= 123/3

x= 41

Verify:

3x + 34=157

3(41)+34=157

123+34=157

157=157

To finish it you will have to complete the sentence which is: Each desk weigh 41 lb.

Here is my next example. This example is also from page 45, letter O.

O. Oshgosh would like to buy a new pair of skates for $115. So far he has saved $40. If he earns $7.50 per hour, how many hours must he work until he can buy the skates?

For this kind of algebraic problem solving, we will do the same thing which is to write a simple sentence. The sentence would be: Oshgosh will have to work for ___ hours to buy the skates.

To complete this sentence you will have to figure out the equation for this algebraic problem solving, answer it and then verify to see if it's correct.

Now you will have to solve the algebraic equation.

7.50x + 40=115

7.50x + 40=115-40

7.50x= 75

7.50x/7.50=115/7.50

x=10

Verify

7.50x + 40=115

7.50(10)+40=115

75+40=115

115=115

To finish this equation you will have to complete the sentence for this algebraic problem solving. The sentence will be: Oshgosh will have to work for 10 hours to buy the skates.

Here is my last example. This example is also from page 45, letter T.

T. Mr. Piper's plumbing needed repairs. The plumber charged $98 for parts plus $45 per hour for labor. If the bill totaled $458, how many hour of labor wee required?

To answer this algebraic problem solving, you will have to figure out what the equation will be for this, and complete a sentence. The sentence will be: ___ hours of labor were required. Also, as always you will have to answer it and verify to see if it's right or wrong.

45x + 98=458

45x + 98=458-98

45x=360

45x/45=360/45

x=8

Verify (Always verify)

45x + 98=458

45(8)+98=458

360+98=458

458=458

Now, to finish off this algebraic problem solving, you will have to complete the sentence for this. The sentence will be: 8 hours of labor were required.

REMEMBER TO STUDY ALGEBRAIC PROBLEM SOLVING FOR THE MATH TEST ON MONDAY! (IF YOU NEED MORE HELP, JUST ASK MR. H).

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linda 8-17said...Wasn't there something to do with like "Let n=____"?

I remember something like that during a previous lesson, and I don't quite remember... I'm pretty sure it's worth marks, so if you could write about that, it'd be beneficial to everyone. Thanks.

January 27, 2009 at 5:48 PM