Answer:
Step-by-step explanation:
Let's solve the second equation for a to later on replace it in the first equation.
Now plug this into the first equation.
Distribute the 9
Break down the fraction.
Simplify.
Subtract 
Combine like terms.
Muliply by the reciprocal or inverted fraction next to b.
Now plug this value into any of the equations to find the value of a.
Answer: First solve the parentheses using order of operations. Then add and subtract from left to right.
Demo:
(3 * 11) = 33
Equation now looks like:
63 - 21 + 33
63 - 21 = 42
Equation now looks like:
42 + 33
42 + 33 = 75
The value of this expression is 75.
Teachers often all this problem a donut problem because it’s like the donut hole getting cut out of the middle. The way that you solve this is to find the area of the whole yard and subtract the area of the fountain. Since they are rectangles we’re going to use A = LW
Area of yard - Area of fountain
A = (8x)(9x) - (2x)(5x)
A = 72 x^2. - 10 x^2
A 62 x^2
Answer:
S
R
T
P
Q
Step-by-step explanation:
Since sin(2x)=2sinxcosx, we can plug that in to get sin(4x)=2sin(2x)cos(2x)=2*2sinxcosxcos(2x)=4sinxcosxcos(2x). Since cos(2x) = cos^2x-sin^2x, we plug that in. In addition, cos4x=cos^2(2x)-sin^2(2x). Next, since cos^2x=(1+cos(2x))/2 and sin^2x= (1-cos(2x))/2, we plug those in to end up with 4sinxcosxcos(2x)-((1+cos(2x))/2-(1-cos(2x))/2)
=4sinxcosxcos(2x)-(2cos(2x)/2)=4sinxcosxcos(2x)-cos(2x)
=cos(2x)*(4sinxcosx-1). Since sinxcosx=sin(2x), we plug that back in to end up with cos(2x)*(4sin(2x)-1)
