X = 15
X + 90 = 7x
X = 7x - 90
X - 7x = -90
-6x = 90
Divide both sides by -6
X = 15
Answer:
4 hours
Step-by-step explanation:
For three visits, the electrician earned $40 × 3 = $120 in "per-visit" charges. For working x hours, he earned 20x in "per-hour" charges. The total of these came to 50x:
120 +20x = 50x
120 = 30x . . . . . . . . subtract 20x
4 = x . . . . . . . . . . . . . divide by 30
The electrician worked 4 hours that day.
<h2><u>Answer</u><u> </u><u>:</u></h2>

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<h2><u>To </u><u>find </u><u>:</u></h2>
- Total number of Floors in dool house
<u>➜</u><u> </u><u>Therefore</u><u> </u><u>,</u><u> </u><u>Total</u><u> </u><u>number</u><u> </u><u>of </u><u>floors</u><u> </u><u>can </u><u>be </u><u>find </u><u>out</u><u> </u><u>by </u><u>dividing</u><u> </u><u>the </u><u>total</u><u> </u><u>height</u><u> </u><u>of </u><u>dollhouse</u><u> </u><u>by </u><u>the </u><u>length</u><u> </u><u>of </u><u>one </u><u>floor</u>


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Answer:
none of them
Step-by-step explanation:
Two lines are perpendicular when satisfy the next equation: m1*m2 = -1, where m1 and m2 are the slopes o the lines.
line 1:
y – 1 = (x+2)
y = x + 3
slope of line 1 = 1
line 2:
y + 2 = –3(x – 4)
y + 2 =
-3*x + 12
y = -3*x + 10
slope of line 2 = -3
m1*m2 = 1*(-3
) = -3
They are not perpendicular
line 3:
y − 5 = 3(x + 11)
y − 5 = 3*x + 33
y = 3*x + 38
slope of line 3 = 3
m1*m3 = 1*3 = 3
They are not perpendicular
line 4:
y = -3x –
slope of line 4 = -3
m1*m4 = 1*(-3
) = -3
They are not perpendicular
line 5:
y = x – 2
slope of line 5 = 1
m1*m5 = 1*1 = 1
They are not perpendicular
line 6:
3x + y = 7
y = -3x + 7
slope of line 6 = -3
m1*m6 = 1*(-3
) = -3
They are not perpendicular
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