The third choice, 4x²+18x+0.25=0, is correct.
The frame will have the same thickness on both sides of the mirror. Therefore we add 5+x+x to get the total length, and we have 4+x+x to get the total width.
The area is found by multiplying the total width and total length:
A=(5+x+x)(4+x+x)
A=(5+2x)(4+2x)
Multiplying the binomials, we have:
A=5*4+5*2x+2x*4+2x*2x
A=20+10x+8x+4x²
A=20+18x+4x²
We know that the area is 19.75:
19.75=20+18x+4x²
We need quadratics set equal to 0, so subtract 19.75 from each side:
19.75-19.75 = 20+18x+4x²-19.75
0=0.25+18x+4x²
In standard form, it will be:
4x²+18x+0.25=0
Answer:
62.5%
Step-by-step explanation:
Answer:
yes, all answers are correct
Step-by-step explanation:
Answer:
Rock D.
Step-by-step explanation:
We can assume that the force that the catapult does is always the same.
So, here we need to remember Newton's second law:
F = m*a
force equals mass times acceleration.
Where acceleration is the rate of change of the velocity.
So, if we want the rock to hit closer to the catapult, the rock must be less accelerated than rock B.
So, we can rewrite:
a = F/m
So, as larger is the mass of the rock, smaller will be the acceleration of the rock after it leaves the catapult (because the mass is in the denominator). So if we want to have a smaller acceleration, we need to choose a rock with a larger mass than rock B.
Assuming that the mass depends on the size, the only one that has a mass larger than rock B is rock D.
So we can assume that rock D is the correct option.
Answer:
Step-by-step explanation:
It is expected the spinner to land on Red 1/5 times.
<u>If the spinner is spun 40 times, then it should land on Red:</u>
<u>And it should not land on red:</u>
- (1 - 1/5)*40 = 4/5*40 = 32 times
Correct choice is D
