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Zigmanuir [339]

3 years ago

8

John took 3 exams so far this semester. He scored 45, 65 and 80 on those 3 exams . What score does he need on the fourth exam to

average 70 or more on his exams?

1 answer:

Olegator [25]3 years ago

3 0

Answer:

$He \: needs \: to \: score \: 90 \: or \: more$

Step-by-step explanation:

$\frac{x + 45 + 65 + 80}{4} \geqslant 70\Leftrightarrow x + 190 \geqslant 280\Leftrightarrow x \geqslant 90$

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Morgarella [4.7K]

Answer:

Step-by-step explanation:

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KE₃₀ = ½(1100)30² = 495000 = 495 kJ

9 times greater

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3 years ago

In the figure,BC andAD are line segments. What is the sum of x and y?

Alika [10]

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4 years ago

Simplify the expressions by combining like terms<br><br> 4r + 9r - 11r + 7r

konstantin123 [22]

9r
Explanation:
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3 years ago

Read 2 more answers

Find the equation of a line that is perpendicular to y = 3x – 5 and passes through the point (1, -3).

Svetradugi [14.3K]

keeping in mind that perpendicular lines have negative reciprocal slopes, let's check for the slope of the equation above

$\begin{array}{|c|ll} \cline{1-1} slope-intercept~form\\ \cline{1-1} \\ y=\underset{y-intercept}{\stackrel{slope\qquad }{\stackrel{\downarrow }{m}x+\underset{\uparrow }{b}}} \\\\ \cline{1-1} \end{array}\qquad \qquad y = \stackrel{\stackrel{m}{\downarrow }}{3}x-5$

well then therefore

$\stackrel{\textit{perpendicular lines have \underline{negative reciprocal} slopes}} {\stackrel{slope}{3\implies \cfrac{3}{1}} ~\hfill \stackrel{reciprocal}{\cfrac{1}{3}} ~\hfill \stackrel{negative~reciprocal}{-\cfrac{1}{3}}}$

so we're really looking for the equation of a line with slope of -1/3 and that passes through (1, -3 )

$(\stackrel{x_1}{1}~,~\stackrel{y_1}{-3})\qquad \qquad \stackrel{slope}{m}\implies -\cfrac{1}{3} \\\\\\ \begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{(-3)}=\stackrel{m}{-\cfrac{1}{3}}(x-\stackrel{x_1}{1})\implies y+3=-\cfrac{1}{3}x+\cfrac{1}{3} \\\\\\ y=-\cfrac{1}{3}x+\cfrac{1}{3}-3\implies y=-\cfrac{1}{3}x-\cfrac{8}{3}$

6 0

2 years ago

Find y when x = 12, if y = 2 when x = 5

AleksAgata [21]

Y = kx
k = y/x
k = 2/12
k = 1/6

so when x = 12
y = kx
y = 1/6(5)
y = 5/6

answer
when x = 5 y = 5/6

7 0

3 years ago