3x - x + 8 + 5x - 2 = 10
combine like terms on the left, then add or subtract as asked
(3x - x + 5x) + (8 - 2) = 10
7x + 6 = 10
subtract 6 from both sides
7x = 4
divide both sides by 7
x = 4/7
Hope this helps! :)
Since the problem is not telling us the height of Silvio, we are going to assume it is not relevant for our calculations.
Let

the altitude of the incoming plane. We know for our problem that the distance between Silvio and the tower is 3 miles, Also we know that the angle of elevation to the plane is 40°. With this information we can create a triangle as shown in the figure. We need a function that relates the angle of elevation with its opposite and adjacent sides, that function is tangent.




We can conclude that we should use the trig function tangent to model this situation; also, we can conclude that the equation that describes this situation is

.
Properties of Logs
logb(x/y) = log<span>bx</span> - log<span>by</span>.
therefore
log5 (4/7)= log5 (4)- log5 (7)
<span>Solve log 5 (4) and log 5 (7) with the base change of the logarithm</span>
<span>log 5 4 = log 4 / log 5 </span>
Use the calculator:
<span>
<span>log 5 4 =0.8613531161
</span></span>
log 5 7 = log 7 / log 5
<span>log 5 7 =1.2090619551</span>
<span>log5 (4/7)= log5
(4)- log5 (7)=-0.347708839</span>
The answer is D
I’m right trust