Answer:
25 cent stamps = 13 and 29 cent stamps = 15
Step-by-step explanation:
x = 25 cent stamps and y = 29 cent stamps
x + y = 28......x = 28 - y
0.25x + 0.29y = 7.60
0.25(28 - y) + 0.29y = 7.60
7 - 0.25y + 0.29y = 7.60
-0.25y + 0.29y = 7.60 - 7
0.04y = 0.60
y = 0.60 / 0.04
y = 15 <===== 29 cent stamps
x + y = 28
x + 15 = 28
x = 28 - 15
x = 13 <===== 25 cent stamps
lets check it...
0.25x + 0.29y = 7.60
0.25(13) + 0.29(15) = 7.60
3.25 + 4.35 = 7.60
7.60 = 7.60 (correct..it checks out)
Answer: This parabola has 0.3875 x-intercepts,
<span>representing the times when the dolphin's height above water is </span>
0 feet.
The x-intercept is the point where the graph crosses the x-axis, which is when the value is y=0.
The calculation for y=0 would be
<span>Y = -16x2 + 32x - 10
</span><span>0 = -16x2 + 32x - 10
</span>-8x2 + 16x - 5=0
-b +-√(b^2-4ac) /2a=
-16 +-√(16^2-4(-8)(-5)) /2(-8) =
-16+- √(256-160/ -16 =
-16+- √(96/ -16 =
-16+- 9.8/ -16 =
x1= 0.3875
x2= -1.6125
That would be :
4x – 10 = x2 – 5x + 10 ( y = 4x - 10 is substitute for y)
PROOF: y + 5x = x²<span> + 10
</span> (4x - 10) + 5x = x² + 10
4x - 10 = x² -5x + 10
<span>
</span>0 = x2 – 9x + 20<span> (liked terms are grouped and simplified)
PROOF: </span> 4x - 10 = x² -5x + 10
4x = x² -5x + 10 + 10
0 = x² -5x -4x + 20
0 = x² - 9x + 20
Solving:
x² - 9x + 20 = 0
x² - 5x - 4x + 20 = 0
(x - 5) (x - 4) = 0
⇒ x = 4 (as question says) OR x = 5
The least common multiple (LCM) can be determined by factoring out the terms first,
165xy = (3)(11)(5)(x)(y)
77x³y = (7)(11)(x)(x)(x)(y)
Copy the factors writing off the repeated factors only once,
LCM = (3)(11)(5)(x)(y)(7)(x)(x)= 1155x³y
The answer is 1155x³y (first choice)
