1) 5(x+2)-7=5x+3

2) Solve -8x+4y=28 for y

3) Find the result when 40 is decreased by 90%

4) Antonio sold a hat for $18. His wholesale cost was $8. What was the percent markup?

5) Alicia bought a prom dress that originally cost $110. After she used a coupon, she spent $82.50 on the dress. What percent discount did she receive?

Thank you so much!

1.) 5(x+2)-7=5x+3
5x+10-7=5x+3
5x+3=5x+3
This is an identity, so it can have any solution. Try some random values in it to test it. Let us try 1 and 2 to begin.
5(1+2)-7=5(1)+3; 5+10-7=5+3; 8=8
5(2+2)-7=5(2)+3; 10+10-7=10+3; 13=13
#2.) -8x+4y=28
4y=8x+28
y=2x+7
#3.)40(1-0.9)
40-36=4
#4.) (18-8)/8=10/8=1.25=125%
#5.) ($110-$82.50)/$110=0.25 =25%

5 Responses

1. Madeline Rose Says:
   January 30th, 2010 at 3:44 am

   1)x=0
   2)y=7+2x
   3)36
   4)idk im terrible at these… sry
   5)75%

   i probably just gave you all the answers to your math homework. oh well ^_^
   References :

2. ALDR Says:
   January 30th, 2010 at 4:05 am

   1) 5(x+2)-7=5x+3
   5x + 10 – 7 = 5x + 3
   5x + 3 = 5x + 3
   x=x could be anything

   2) Solve -8x+4y=28 for y
   4y = 28 + 8x
   y = 7 + 2x

   3) Find the result when 40 is decreased by 90%
   40 – 0.90(40) = 40 – 36 = 4

   4) Antonio sold a hat for $18. His wholesale cost was $8. What was the percent markup?
   (18 – / = 1.25 = 125%

   5) Alicia bought a prom dress that originally cost $110. After she used a coupon, she spent $82.50 on the dress. What percent discount did she receive?
   (110 – 82.5) / 110 = 0.25 = 25%
   References :

3. ElaineGSD Says:
   January 30th, 2010 at 4:28 am

   For the first two problems, multiply out and simplify. The first one will yield something like "x = ???" Let’s work through the second one.

   -8x + 4y = 28 we are solving for y, so let’s add 8x to both sides
   -8x + 4y + 8x = 28 + 8x and simplify
   4y = 8x + 28 now let’s divide both sides by 4
   4y/4 = 8x/4 + 28/4 and simplify again
   y = 2x + 7

   The third, fourth and fifth problems are also the same, they are word problems dealing with percentages. Let’s look at the third problem.

   Alicia spent $82.50 on a $110 dress, which means she saved
   $110 – $82.50 = $27.50. What percentage of $110 is $22.5?

   $27.5/110 = .25 and to make this a percentage, we mutliply by 100/100
   .25 * (100/100) = 25 percent.
   References :

4. Chen-Chu L Says:
   January 30th, 2010 at 5:02 am

   1.) 5(x+2)-7=5x+3
   5x+10-7=5x+3
   5x+3=5x+3
   This is an identity, so it can have any solution. Try some random values in it to test it. Let us try 1 and 2 to begin.
   5(1+2)-7=5(1)+3; 5+10-7=5+3; 8=8
   5(2+2)-7=5(2)+3; 10+10-7=10+3; 13=13
   #2.) -8x+4y=28
   4y=8x+28
   y=2x+7
   #3.)40(1-0.9)
   40-36=4
   #4.) (18-8)/8=10/8=1.25=125%
   #5.) ($110-$82.50)/$110=0.25 =25%
   References :

5. Kobayashi Says:
   January 30th, 2010 at 5:13 am

   ALDR and Chen-Chu have same answers, I think they are corect, I have same answers too.
   1) Any number work here.
   2) y = 2x+7
   3) 4
   4) 125%
   5) 25%
   References :

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