Step-by-step explanation:
(4s + 2) × (5s² + 10s +3)
we know immediately the first and the last term of the result, because there is only one operation to build them :
20s³ and 6.
so, the first answer option is already eliminated.
let's multiply
4s×5s² + 4s×10s + 4×3s + 10s² + 20s + 6
20s³ + 40s² + 12s + 10s² + 20s + 6
20s³ + 50s² + 32s + 6
so, the last answer option is correct.
Answer:
8.69565217391 m per sec
8.7 (1dp)
Step-by-step explanation:
If we multiply the bottom equation by 2 and move x to the right, it becomes:
4y = 2x-38
Now we can substitute it for the 4y in the top equation:
3x + (2x-38) = -23 => 5x = -23+38 => 5x = 15 => x=3
Then 4y = 2*3-38 => y = -8
So the solution is (3,-8)
The sequence is an geometric progression;
Nth=a₁r^(n-1)
a₁ is the first term=-1
r=ratio=a₂/a₁=6/-1=-6
Nth=-1(-6^(n-1)
NTh=an
a₁=-1(-6⁰)=-1
a₂=-1(-6¹)=6
a₃=-1(-6²)=-36
a₄=-1(-6³)=216
therefore this serie is rising at an increasing fast speed, it is an geometric progression.
Given

We have to set the restraint

because a square root is non-negative, and thus it can't equal a negative number. With this in mind, we can square both sides:

The solutions to this equation are 7 and -2. Recalling that we can only accept solutions greater than or equal to -1, 7 is a feasible solution, while -2 is extraneous.
Similarly, we have

So, we have to impose

Squaring both sides, we have

The solutions to this equation are 5 and 10. Since we only accept solutions greater than or equal to 7, 10 is a feasible solution, while 5 is extraneous.