Multiple 2x * 5x =10x^2
Multiple 2x * -1 = -2x
Multiple 6 * 5x = 30x
Multiple 6 * -1 = -6
Add 30x + (-2x) = -28x
10x^2 + 28x -6 is the final answer
Answer:
B
Step-by-step explanation:
We have the following equation:
x2 + 4x = - (y2 - 20)
Let's review step by step:
step 1:
x2 + 4x = -y2 + 20
Answer: OK
step 2:
x2 + 4x + 4 = -y2 + 20 - 4
Answer: Wrong
The correct step is:
x2 + 4x - 4 = -y2 + 20 - 4
Or equivalently:
x2 + 4x + 4 = -y2 + 20 + 4
Answer:
he did make an error in his work in step 2
In a trapezoid, with bases 
and 
and height 
, the area is given by
In your case:
so, the formula becomes
Since the area is 
, we have
