Answer:
S=157
Step-by-step explanation:
an= a1+(n-1)d
a2=80+(2-1)(-3)
a2=80-3
a2=77
Sn=(a1+an)*n/2
S2=(80+a2)*2/2
S2=(80+77)*1
S2=157
Answer:
9 and -5
Step-by-step explanation:
9*-5=-45
9+-5=4
Answer: 490 grams of the first alloy should be used.
30 grams of the second alloy should be used.
Step-by-step explanation:
Let x represent the weight of the first alloy in grams that should be used.
Let y represent the weight of the second alloy in grams that should be used.
A chemist has two alloys, one of which is 15% gold and 20% lead. This means that the amount of gold and lead in the first alloy is
0.15x and 0.2x
The second alloy contains 30% gold and 50% lead. This means that the amount of gold and lead in the second alloy is
0.3y and 0.5y
If the alloy to be made contains 82.5 g of gold, it means that
0.15x + 0.3y = 82.5 - - - - - - - - - - - -1
The second alloy would also contain 113 g of lead. This means that
0.2x + 0.5y = 113 - - - - - - - - - - - - -2
Multiplying equation 1 by 0.2 and equation 2 by 0.15, it becomes
0.03x + 0.06y = 16.5
0.03x + 0.075y = 16.95
Subtracting, it becomes
- 0.015y = - 0.45
y = - 0.45/- 0.015
y = 30
Substituting y = 30 into equation 1, it becomes
0.15x + 0.3 × 30 = 82.5
0.15x + 9 = 82.5
0.15x = 82.5 - 9 = 73.5
x = 73.5/0.15
x = 490
Answer:
Step-by-step explanation:
The slope-intercept form is given by y=mx+c, where m is the slope and c is the y-intercept.
Slope of given line= 
Parallel lines have the same slope. Thus, the slope of the line would also be .
The value of c can be found by substituting a pair of coordinates.
When x= 4, y= -1,
-1= -3 +c
<em>Add 3 to both sides:</em>
c= -1 +3
c= 2
Thus, the equation of the line is 
.
Additional:
Do check out the following for a similar question on slope-intercept form!
