1. 1/7 (x-3) =1/8 (x-2)
2. 1/4 (x-7)= 1/5 (x-8)
3.-(6x+5) - (9x-7) =11 - (5x+1)
2007-09-20 16:57:04 · 6 answers · asked by GO Saints!! 3 in Science & Mathematics ➔ Mathematics
1)1/7(x-3)=1/8(x-2)
Multiplying both sides by 56,the LCM of the denominators 7 and 8,we get
56*1/7(x-3)=56*1/8(x-2)
8(x-3)=7(x-2)
8x-24=7x-14
8x-7x=-14+24
x=10 ans
2.1/4(x-7)=1/5(x-8)
multiplying both sides by 20,we get
5(x-7)=4(x-8)
5x-35=4x-32
5x-4x= -32+35
x=3
3)-(6x+5)-(9x-7)=11-(5x+1)
-6x-5-9x+7=11-5x-1
-6x-9x+5x=11-1+5-7
-10x=8
x=8/-10= -4/5
2007-09-20 17:06:37 · answer #1 · answered by alpha 7 · 0⤊ 1⤋
1. You can multiply both sides by the least common denominator, which is 56, and you get:
1/7 * (x - 3) = 1/8 * (x - 2).
8 * (x - 3) = 7 * (x - 2).
8x - 24 = 7x - 14.
8x - 7x = -14 + 24.
x = 10.
2. The same works here, multiplying both sides by 20.
1/4 * (x - 7) = 1/5 * (x - 8).
5 * (x - 7) = 4 * (x - 8).
5x - 35 = 4x - 32.
5x - 4x = -32 + 35.
x = 3.
3.) For this one, you need to evaluate the expressions in parentheses and then move x to the left side.
-(6x + 5) - (9x - 7) = 11 - (5x + 1).
-6x - 5 - 9x + 7 = 11 - 5x - 1.
-15x + 2 = 10 - 5x.
-15x + 5x = 10 - 2.
-10x = 8.
x = -4/5.
2007-09-21 00:13:22 · answer #2 · answered by RustyL71 4 · 0⤊ 0⤋
Hello,
1. mul both sides by 56 giving 8x-24 = 7x-14 so x = 10
2. Multiply boths sides by 20 and we have 5x-35 = 4x -32 or x = 3
3. Multiply everything by -1 giving us 6x+5 +9x-7=-11+5x+1
colecting like terms 15x -2 = 5x -10 so 10x = -8 or x=-.8.
Hope This Helps!!
2007-09-21 00:08:14 · answer #3 · answered by CipherMan 5 · 0⤊ 0⤋
1. distribute the 1/7 to the x and -3 and the 1/8 to the x and -2:
1/7x - 3/7=1/8x-1/4
subtract 1/8x from both sides and add 3/7 to both sides:
1/56x=5/28
divide both sides by 1/56:
x=10
2.distribute the 1/4 to the x and -7 and the 1/5 to the x and -8:
1/4x - 7/4= 1/5x - 8/5
subtract 1/5x from both sides and add 7/4 to both sides:
1/20x=3/20
divide both sides by 1/20:
x=3
3. distribute the negative to 6x+5, 9x-7, and 5x+1
-6x-5-9x+7=11-5x-1
collect like terms on each side:
-15x+2=-5x+10
substract 10 from both sides and add 15x to both sides:
-8=10x
divide both sides by 10 and reduce:
x= -4/5
2007-09-21 00:12:24 · answer #4 · answered by Anonymous · 0⤊ 0⤋
1) multiply by 56
8x-24=7x-14
8x-7x=0-14+24
x=10
check
10/7-3/7=10/8-2/8
1=1
correct
2) multiply by 20
5x-35=4x-32
x=3
check
3/4-7/4=3/5-8/5
-1=-1
correct
3)-6x-5-9x+7=11-5x-1
(((why +7 because think of -(9x-7) as -1(9x-7)
and minus times minus=plus)))
-6x-9x+5x=5-7+11-1
somewhere i have gone wrong but anyway help it hopes
2007-09-21 00:39:46 · answer #5 · answered by GOLD-FLAW 2 · 0⤊ 0⤋
too lazy... but i'll solve 1 for ya, as it's similar to 2.
1) Multiply both sides by 56, a common multiple of 7 and 8 (denominators)
you get:
8 (x-3) = 7 (x-2)
expand. 8x - 24 = 7x -14
x's on one side. x - 24 = -14
numbers on the other. x = 10.
check. solved.
hope that helps.gtgkkbye.
2007-09-21 00:06:19 · answer #6 · answered by Anonymous · 0⤊ 0⤋