I am so lost.
Rational Expressions: SOLVE:
z-6/z+7 = 5/7
The problem above is in fraction form.
2007-08-22 08:34:59 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Cross multiplication gives,
7z-42 = 5z+35
z = 77/2
2007-08-22 08:42:12 · answer #1 · answered by sahsjing 7 · 1⤊ 0⤋
When two fractions equal each other, you can cross multiply and set the products equal to each other. So,
7(z - 6) = 5(z + 7)
7z - 42 = 5z + 35
2z - 42 = 35
2z = 77
z = 77/2
2007-08-22 15:45:39 · answer #2 · answered by FIESTA 3 · 0⤊ 0⤋
Z = 38.5 or 77/2
here's how:
z-6 = (5/7)(z+7)
7(z-6)=5(z+7)
7z-42=5z+35
7z=5z+77
2z=77
z=77/2=38.5
2007-08-22 15:48:45 · answer #3 · answered by mittu90 2 · 0⤊ 0⤋
(z-6)/(z+7) = 5/7
5(z+7) = 7(z-6)
5z+35 = 7z-42
-2z = - 77
z = 77/2 = 38.5
2007-08-22 15:50:05 · answer #4 · answered by ironduke8159 7 · 0⤊ 0⤋
cross multiply first than move variables to one side than divide
7z-42=5z+35
2z=77
z=77/2
2007-08-22 15:50:34 · answer #5 · answered by ddddowntown 1 · 0⤊ 0⤋
oh! its too easy.Its a qudratic eqn
multiply both sides by z.so z^2-6+7z=5z/7.
7z^2+(49-5)z-42=0
7z^2+44z-42=0
The 2 roots of this eqn can now be easily found out.
2007-08-22 15:45:59 · answer #6 · answered by Varun 2 · 0⤊ 0⤋