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Question 75051: Stan thanks for your help ,i have 20 of these to do can you please help me thanks a millon .
2. Find the equation of the line with a slope of -5 and passes through the point (2, -4).
3. Write an equation of the line that passes through (0, -4) and is parallel y = (3/4)x + 2. Write the answer in slope-intercept form.
4. Solve the system of equations by substitution:
x + 2y = 9
3x - y = 13
5. Solve the system of equations by substitution:
4x - 3y = 1
12x - 9y = 3
Answer by checkley75(3666)   (Show Source):
You can put this solution on YOUR website! 2) SLOPE=-5 THROUGH POINTS(2/-4)
USING THE LINE FORMULA Y=mX+b WHRE m=SLOPE & b=Y INTERCEPT.
USING THE GIVEN POINT (X,Y) SUBSTITUTED IN THE LINE FORMULA ALONG WITH THE SLOPE WE CAN NOW FIND THE Y INTERCEPT THUS:
-4=-5*2+b
-4=-10+b
b=-4+10
b=6 SO THE EQUATION IS
Y=-5X+6
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3) LINE THROUGH (0,-4) WITH SLOPE =3/4 ( SAME SLOPE AS THE LINE IT IS PAERALLEL WITH.
Y=mX+b
-4=3/4*0+b
-40+B
b=-4 THUS THE FORMULA IS
Y=3/4X-4
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4) X+2Y=9, X=-2Y+9
3X-Y=13 NOW SUBSTITUTE (-2Y+9) FOR X IN THIS EQUATION & SOLVE FOR Y
3(-2Y+9)-Y=13
-6Y+27-Y=13
-7Y=13-27
-7Y=-14
Y=-14/-7
Y=2 ANSWER.
X=-2*2+9
X=-4+9
X=5 ANSWER.
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5) 4X-3Y=1, 4X=3Y+1, X=3Y/4+1/4
12X-9Y=3 NOW SUBSTITUTE (3Y/4+1/4) FOR X & SOLVE FOR Y
12(3Y/4+1/4)-9Y=3
36Y/4+12/4-9Y=3
9Y+3-9Y=3
0Y=3-3
0Y=0 NO SOLUTION HERE.
THESE TWO FORMULAS ARE THW SAME WITH TWO VARIABLES.
ERGO NO UNIQUE SOLUTION FPR X & Y.
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