what is the answer to this equation?? I get 12 but the answer sheet says 20.
If 3x-1=11, what is the value of x2+x ?
2007-07-16 07:51:49 · 6 answers · asked by Bianca 3 in Science & Mathematics ➔ Mathematics
solve for x:
3x - 1 = 11
3x = 12
x = 4
x = 4
__________
2x + x
2(4) + 4
8 + 4
12
the answer is 12
__________
UNLESS it means:
x^2 + x
4^2 + 4
16 + 4
20
thats more like it.
2007-07-16 07:57:46 · answer #1 · answered by Link 4 · 0⤊ 0⤋
The answer sheet´s right:
3x - 1 = 11 ==> 3x = 12 ==> x = 4, and thus input x = 4 in x^2 + x and get:
4^2 + 4 = 16 + 4 = 20.
Regards
Tonio
2007-07-16 14:58:50 · answer #2 · answered by Bertrando 4 · 0⤊ 0⤋
x = 4, so that x^2 + x = 16 + 4 = 20.
You need to use a math-writing convention that doesn't confuse you. (You probably MULTIPLIED x by 2, instead of recognizing that ' 2 ' was intended to be an EXPONENT. That kind of thing is typed in as x^2, where ' ^ ' can be found above the ' 6 ' on your keyboard.)
In greater detail, the original equation was:
3x - 1 = 11 (Use spacing for clarity.)
Therefore 3x = 12, that is x = 4.
As stated above, this implies x^2 + x = 4^2 + 4 = 16 + 4 = 20.
You, however, presumably misinterpreted the desired result as
x*2 + x = 4*2 + 4 = 8 + 4 = 12.
This problem illustrates the importance of using clear notation.
Live long and prosper.
2007-07-16 14:57:17 · answer #3 · answered by Dr Spock 6 · 0⤊ 0⤋
3x-1=11
or 3x=11+1=12
or x=12/3=4
Therefore x^2+x
=4^2+4
=16+4=20
2007-07-16 14:57:41 · answer #4 · answered by alpha 7 · 0⤊ 0⤋
3x=12
12/3=4=x
4 squared=16+4 = 20
2007-07-16 14:57:57 · answer #5 · answered by Kassidee 3 · 0⤊ 1⤋
3x = 12
x = 4
x^2 + x = 20
2007-07-16 14:58:52 · answer #6 · answered by gebobs 6 · 0⤊ 0⤋