Tan9−tan27−tan63−tan81
tan9+tan81−tan27−tan63
sin9/cos9+sin81/cos81−sin27/cos27−sin63/cos63
sin90/cos81cos9−sin90/cos63cos27
1/sin9cos9−1/sin27cos27
2/sin18−2/sin54
(2)sin54−sin18/sin18sin54
4cos36sin18/sin18cos36=4
"Isolate the constant by adding 7 to both sides of the equation."
This step separates the non-squareable 7 and the squareable
.
"Add 9 to both sides of
to form a perfect square trinomial while keeping the equation balanced."
After separating the non-squareable, add the number which makes the first or left side a perfect square trinomial. The formula to find the number is:
.
When we plug the values:
Simplify:
"Write the trinomial
as
squared."
When you factor
, you will get
.
"Use the square root property of equality to get
."
The 16 is coming from the part when we add 9. We needed 9 on the left side for a perfect square, but to protect the balance of the equality, we need to add 9 to the right side too. When we add 7 and 9, we got 16, and that is where it came from.
"Isolate the variable x to get solutions of -1 and 7."
To isolate x we branched the plus-minus sign:
Answer:
b, d
Step-by-step explanation:
20/-4 = -5
20 x (-1/4) = -5
We have to calculate the total cost of the meal. We know that Adam ( A ) and his dad ( D ) share the cost of the meal in the ratio 2 : 3 and that Adam`s dad pays 52.20 Pounds. So A : D = 2 : 3; A : 52.20 = 2 : 3. Using the cross products, A * 3 = 2 * 52.20; A * 3 = 104.40; A = 104.40 : 3; A = 34.80 Pounds. Finally, A + D = 34.80 + 52.20 = 87.00. Answer: The total cost of the meal is 87 Pounds<span>. </span>