Answer:(b). 4I2-81
Step-by-step explanation:(2I+9)(2I-9)
=4I2-18I+18I-81
=4I2-81
We know the opposite side (10) and the adjacent side (7), so we can use tangent to find angle B. Since tan = opposite side/adjacent side, we can set up this equation: tan(B) = 10/7. We can get B on its own by making the equation this:

Now, we plug this into our calculator to get:
B = 55°, so angle B is 55°.
Let me know if you need any more help!
Let's start with triangle RST. This is a 30-60-90 triangle, which means it has the relationship x - x sqrt(3) - 2x.
If RS is 2 sqrt(3), then ST must be 2 and RT must be 4.
Triangle QRT is a 45-45-90 triangle, which means it has the relationship x - x - x sqrt(2).
If RT is 4, then RQ must also be 4.
Answer: x = 4
Hope this helps!
Answer:
Fast car = 45.6
Slower car = 30.4
Step-by-step explanation:
Let the speed of the first car = x
Let the speed of the second car = y
Travelling towards each other.
x *1 + y*1 = 76 miles
x*5 - y*5 = 76 miles. This is kind of tricky. You have to understand that the first car that is 76 miles from the second car and makes up that 76 in 5 hours. The distance they both travel is subtracted out.
Divide by 5
x - y = 76/5
x - y = 15.2 The speeds differ by 15.2
x + y = 76
x - y = 15.2
2x = 91.2
x = 45.6
y = 76 - 45.6 = 30.4
When the two vehicles speeds are multiplied by 5, the difference is 76 km
your answer should be 160
b if you times both of the numbers