Answer:
x=17 plz the brainliest!
Step-by-step explanation:
3x+39=90
3x+39-39=90-39
3x=51
\frac{3x}{3}=\frac{51}{3}
x=17
(Credit to guy/girl above) 63 miles 10 1/2 x 6 is 63.
Looks like the system is
We can eliminate 
by taking
so that 
, and
Substitute into this last equation and solve for 
:
Then
Plug these values into any one of the original equation to solve for :
Hence the solution is x = 4, y = -3, and z = 2.
Answer:
Rewrite the equation as
3
b
+
4
c
=
a
.
3
b
+
4
c
=
a
Subtract
4
c
from both sides of the equation.
3
b
=
a
−
4
c
Divide each term by
3
and simplify.
Tap for more steps...
b
=
a
3
−
4
c
3
Step-by-step explanation:
let the speed of plane in still air be x and that wind be y
therefore:
x+y=490
x-y=390
next we solve for the values of x and y, first we add the above equations. This will give us:
2x=880
x=880/2
x=440 miles per hour.
substituting the value of x in one of the equations and solving for y we get:
440+y=490
y=490-440
y=50 miles per hour
