2/3x=10
x=10÷2/3
x=10×3/2
x=5×3
x=15
Thank you for posting your math question here at brainly. Among the choices provided the equation can used to find how many hours Melania worked in both jobs is letter B which is "13c + 9.25(38 – c) = 434" I hope it helps.
Answer:
9/16
Step-by-step explanation:
First, note that 10000 multiplied by .5625 will get rid of the decimal point. Therefore, make a fraction where the numerator is .5625 times 10000 and denominator is 10000 like this:
.5625 x 10000
10000
Next, multiply the numbers in the numerator together and keep the denominator as is. Now our fraction looks like this:
5625
/10000
The greatest common factor of 5625 and 10000 is 625, which means you can divide the numerator and denominator by 625 and keep the same value:
5625 ÷ 625
/10000 ÷ 625
And when calculating the numerator and denominator in our fraction above, we get .5625 as a fraction in the simplest form possible:
.5625 =
9
/16
First we use sin(a+b)= sinacosb+sinbcosa
and cos(a+b)=cosa cosb -sinasinb
tan(x+pi/2)= sin(x+pi/2) / cos(x+pi/2)
and sin(x+pi/2) = sinxcospi/2 + sinpi/2cosx =cosx,
<span>cos(x+pi/2) = cosxcospi/2- sinxsinpi/2= - sinx,
</span> because <span>cospi/2 =0, </span>and <span>sinpi/2=1
</span><span>=tan(x+pi/2)= sin(x+pi/2) / cos(x+pi/2)= cosx / -sinx = -1/tanx = -cotx
</span>from where <span>tan(x+pi/2)=-cotx</span>
