Answer:
d = log 38/log31
d = 1.06
Step-by-step explanation:
31 ^ d = 38
Take log of both sides since the exponential equation have different base (always)
d log 31 = log 38
d = log 38 / log 31
d = 1.58 / 1.491
d = 1.06.
We can actually check to see if this is correct.
Substituting d = 1.06
31^ 1.06 = 38.092
(You see, that's approximately correct)
Keep learning, maths is fun!
Answer:a=4
Step-by-step explanation:
Expand the brackets. Collect like terms. Get the same values on each side so it’s easier to isolate a. Divide 9 from 9a so that u get a by itself and this gives u the answer if 36/9 or 4.
Here i how I would do it:<span>f(x)=−<span>x2</span>+8x+15</span>
set f(x) = 0 to find the points at which the graph crosses the x-axis. So<span>−<span>x2</span>+8x+15=0</span>
multiply through by -1<span><span>x2</span>−8x−15=0</span>
<span>(x−4<span>)2</span>−31=0</span>
<span>x=4±<span>31<span>−−</span>√</span></span>
So these are the points at which the graph crosses the x-axis. To find the point where it crosses the y-axis, set x=0 in your original equation to get 15. Now because of the negative on the x^2, your graph will be an upside down parabola, going through<span>(0,15),(4−<span>31<span>−−</span>√</span>,0)and(4+<span>31<span>−−</span>√</span>,0)</span>
To find the coordinates of the maximum (it is maximum) of the graph, you take a look at the completed square method above. Since we multiplied through by -1, we need to multiply through by it again to get:<span>f(x)=31−(x−4<span>)2</span></span><span>
Now this is maximal when x=4, because x=4 causes -(x-4)^2 to vanish. So the coordinates of the maximum are (4,y). To find the y, simply substitute x=4 into the equation f(x) to give y = 31. So it agrees with the mighty Satellite: (4,31) is the vertex.</span>
Answer:
Step-by-step explanation:
15·x²=15·x so
x²=x
x·x=x with x≠0 than x must be 1
x=1
