Question

-7/20f+2/5=1/4f what does f equal (show work) 4

Answer 1

\[-\frac{7}{20}f+\frac{2}{5}=\frac{1}{4}f\]
get your f's together
add 7f/20 on both sides
\[\frac{2}{5}=\frac{1}{4}f+\frac{7}{20}f\]
find a common denominator
\[\frac{2}{5}=\frac{5}{20}f+\frac{7}{20}f\]
\[\frac{2}{5}=\frac{12}{20}f\]
we can simplify 12/12
\[\frac{2}{5}=\frac{3}{5}f\]
\[\frac{5}{3}*\frac{2}{5}=f\]

Answer 2

2/5=1/4f+7/20f
2/5=5/20f+7/20f
2/5=12/20f
4f=60
f=15

Answer 3

i get f=2/3 lets check

Answer 4

40f=60
f=3/2

Answer 5

a7med did you do f=20/12*2/5

Answer 6

20f*2=5*12

Answer 7

so you tried to cross multipliy
so it should be 5*12f=2*20

Answer 8

thank u

Answer 9

no, u 20f*2=5*12
i'm sure

Answer 10

we have 12f/20=2/5
to get f by itself we multiplied by the reciprocal of 12/20 on both sides giving us
(20/12)(12f/20)=(20/12)(2/5)
f=40/60=2/3

Answer 11

we can also check f=2/3
so we plug 2/3 whereever we see an f in the orignal problem
(-7/20)(2/3)+2/5=(1/4)(2/3)
-14/60+2/5=2/12
-7/30+2/5=2/12
-7/30+12/30=2/12
5/30=2/12
1/6=1/6
2/3 is definitely correct!