Question 189987
Please help I have tried and cant come up with the solution.
. Find the equation, in standard form, of the line perpendicular to 2x - 3y = -5 and passing through (3, -2). Write the equation in standard form, with all integer coefficients.
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First we have to find the slopes, we need it in the slope intercept form for this:
2x - 3y = -5; this is the standard form
-3y = -2x - 5
Get rid of all those negatives, multiply eq by -1
3y = 2x + 5
Divide by 3 to get y
y = {{{2/3}}}x + {{{5/3}}}
The slope of this equation (m1) is {{{2/3}}}
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Find the slope (m2) of the perpendicular line:  m1*m2 = -1
{{{2/3}}}*m2 = -1
m2 = -1 * {{{3/2}}}
m2 = {{{-3/2}}} is the slope of the perpendicular line
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It passes thru 3,-2 write the equation using the point/slope form y-y1 = m(x-x1)
y - (-2) = {{{-3/2}}}(x - 3)
y + 2 = {{{-3/2}}}x + {{{9/2}}}
y = {{{-3/2}}}x + {{{9/2}}} - 2
y = {{{-3/2}}}x + {{{9/2}}} - {{{4/2}}}
y = {{{-3/2}}}x + {{{5/2}}} is the equation
To put it in the standard form, multiply equation by 2
2y = -3x + 5
+3x + 2y = 5 is the standard form of the perpendicular line
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Check it using the given coordinates 3, -2
3(3) + 2(-2) = 5
9 - 4 = 5, confirms our equation
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4. Solve the system of equations using the substitution method.
If the answer is a unique solution, present it as an ordered pair: (x, y). If not, specify whether the answer is "no solution" or "infinitely many solutions" and state how you arrived at that conclusion.
3x + y = 2
2x - y = 3
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Use the 1st equation for substitution 
y = -3x + 2
Substitute (-3x+2) for y in the 2nd equation
2x - (-3x+2) = 3
2x + 3x - 2 = 3; minus a minus is a plus
5x = 3 + 1
5x = 5
x = 1
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Substitute 1 for x in the 1st equation find y
3(1) + y = 2
3 + y = 2
y = 2 - 3
y = -1
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Check solutions in the 2nd equation (2x - y = 3)
2(1) - (-1) = 3
2 + 1 = 3; confirms our solutions, ordered pair: 1, -1
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5. Solve the system of equations using the addition (elimination) method.
If the answer is a unique solution, present it as an ordered pair: (x, y). If not, specify whether the answer is "no solution" or "infinitely many solutions" and state how you arrived at that conclusion.
3x - 11y = 9
-9x + 33y = -27
multiply the 1st equation by 3, add to the 2nd equation
+9x - 33y = 27
-9x + 33y = -27
-------------------adding eliminates everything, there is no solution
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6. Solve the system of equations using the addition (elimination) method.
If the answer is a unique solution, present it as an ordered pair: (x, y). If not, specify whether the answer is "no solution" or "infinitely many solutions" and state how you arrived at that conclusion.
4x + 10y = 2
3x + 5y = 5 
Multiply the 2nd equation by -2 add to the 1st equation
+4x + 10y = 2
-6x - 10y = -10
------------------adding eliminates y, find x
-2x = -8
x = {{{(-8)/(-2)}}} 
x = +4
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Find y using the 1st equation
4(4) + 10y = 2
16 + 10y = 2
10y = 2 - 16
10y = -14
y = {{{(-14)/10}}}
y = -1.4
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Check solution in the 2nd equation:
3(4) + 5(-1.4) = 5
12 - 7 = 5; confirms our solutions, ordered pair: 4, -1.4