math help please

Question

solve for y. 3_x-6y+12=0

  number two

solve for x. |x -2|+5=3

number three

| 8-5_x | + 2+4

number four

| 3_x - 7 |= | 3_x +7 |
  number five

The perimeter of a rectangle is 88inches. if the length of the rectangle is eight inches more than three times the width, find the dimensions.

    number six

Barney invested $80,000 in two investment. the first part was invested at 3% interest and the remainder was invested at 4% interest. the total interest he received at the end of one year was 3,000. How much money was invest at 3%?

  

  number seven

How many pounds of candy worth 50cent per pound and how many pounds of peanuts worth 90 cent per pound must be mixed to get a mixture of 64 pound worth 60 cent per pound.

 is it A) 16 lbs. .nuts and 48lbs. candy   (b)48 lbs nuts and 16 lbs.candy  (c)32 lbs..nuts and 32lbs candy (d) 8lbs.nuts and 56lbs.candy

   thank you as you help

Answer 1

3x-6y+12=0

3x+12=6y

(3x/6)+12/6=y

(x/2)+2=y

 

lx-2l+5=3

lx-2l=-2

no solution because absolute value can never be negative

 

I'll assume you mean l8-5xl+2=4

8-5x+2=4

10-5x=4

-5x=-6

x=6/5

also, 5x-8+2=4

        5x-6=4

        5x=10

          x=2

 

l3x-7l=l3x+7l

case 1: 3x-7=3x+7, -7=7, no solution

case 2:  3x-7=-3x-7, 6x=0, x=0

case 3:  -3x+7=3x+7, -6x=0, x=0

case 4:  -3x+7=-3x-7, 7=-7, no solution

 

w=width

3w+8=length

P=2l+2w

88=2(3w+8)+2w

88=6w+16+2w

88=8w+16

72=8w

w=9 inches

3*9+8=27+8=35

l=35 inches

check: 88=35+35+9+9=70+18=88

 

I=prt

3000=3%x+4%(80,000-x)

3000=0.03x+0.04(80,000-x)

3000=0.03x+3200-0.04x

3000=-0.01x+3200

-200=-0.01x

200=0.01x

$20,000=x (invested at 3%)

$80,000-$20,000=$60,000 invested at 4%

 

50x+90(64-x)=64(60)

50x+5760-90x=3840

-40x+5760=3840

-40x=-1920

40x=1920

x=48 lbs of candy and 64-48=16 lbs of nuts; A) is the answer