Answer:
a. 15 meters.
b. 20 meters.
Step-by-step explanation:
a. The height of the ball at 3 seconds. 20 * 3 - 5 * (3)^2 = 60 - 5 * 9 = 60 - 45 = 15.
The ball will be 15 meters high.
b. The maximum height reached by the ball.
To get that, we need to find the vertex of the parabola. We do so by doing -b/2a to find the x-coordinate of the vertex.
In this case, a = -5 and b = 20.
-20 / 2(-5) = -20 / -10 = 20 / 10 = 2.
Then, we find the y-coordinate by putting 2 where it says "t".
h(2) = 20(2) - 5(2)^2 = (40) - 5(4) = 40 - 20 = 20 meters.
Hope this helps!
Answer:
Step-by-step explanation:
Let the height = h
Let the base = 4h + 7
Area of a triangle = 1/2 * b * h
Area = 93 square inches
1/2 * (4h + 7)* h = 93 Multiply both sides by 2
(4h + 7) * h = 93*2
(4h + 7)*h = 186 Remove the brackets
4h^2 + 7h = 186 Subtract 186 from both sides.
4h^2 + 7h - 186 = 0
Use the quadratic formula to solve
a = 4
b = 7
c = - 186
x1 = (-7 + sqrt(7^2 - 4*4*(-186) ) /2*4
x1 = (-7 + sqrt(49 - 16*(-186)) / 8
x1 = (-7 + sqrt(49 + 2976)) / 8
x1 = (-7 + sqrt(3025)) / 8
x1 = (-7 +55 ) / 8
x1 = (48)/8
x1 = 6
There is another root, but it has to be minus and therefore cannot be used as a length. x2 = - 7.75
h = 6
b = 4*6 + 7 = 31
Check
Area = 1/2 * b * h
Area = 1/2 * 31 * 6
Area = 1/2 *186
Area = 93 which is what we were given so the answer is correct.
The coefficient in (4x-2) is the -2
A two-digit number is twice the sum of its digit. If the tens digit is 7 less than the unit digit, find the number.
Let x= the unit digit
Then y= the tens digit
<span>And 10y+x= the number
</span>x+y= the sum of the digits
<span>Now we are told that 10y+x=2(x+y) ------1st equation </span>
<span>We are also told that y=x-7 ----------- 2nd Equation </span>
<span>So our equations to solve are: </span>
(1) 10y+x=2(x+y)
<span>(2) y=x-7
</span>
Hope it helps
Answer:
the answer is C
Step-by-step explanation:
