Question

solve the system of equations
9x-3y=36
7x-3y=45

Answer 1

multiply the 1st equation by -1 and then use the elimination method.
Can you do that ?

Answer 2

-9x+3y=-36
7x-3y=45
-2x=8
x=-4

Answer 3

you found the x....now sub -4 in for x in either of the equations to find y

Answer 4

wait......x is wrong...try that again

Answer 5

-3y = 36 - 9x
3y = 9x - 36
y = 3x - 12

7x - 3(3x - 12) = 45
7x - 9x + 36 = 45
-2x = 9
x = -9/2

y = 3x - 12
y = 3(-9/2) - 12
y = (-27 - 24)/2
y = -51/2

Answer 6

isn't the answer (9,6)

Answer 7

no.....its gonna be a fraction....huiyingtanyayap just did it for you using the substitution method

Answer 8

let me check her answers...hold on

Answer 9

9x - 3y = 36
9(-9/2) - 3(-51/2) = 36
-81/2 + 153/2 = 36
-72/2 = 36
-36 = 36...
no those answers are not correct....
Let me do it....hold on

Answer 10

9x - 3y = 36
-3y = 36 - 9x (multiply by -1)
3y = 9x - 36
y = 3x - 12

7x - 3y = 45
7x - 3(3x - 12) = 45
7x - 9x + 36 = 45
-2x = 45 - 36
-2x = 9
x = -9/2

9x - 3y = 36
9(-9/2) - 3y = 36
-81/2 -3y = 36
-81/2 - 36 = 3y
-81/2 - 72/2 = 3y (multiply the equation by 2)
-81 - 72 = 6y
-153 = 6y
-153/6 = y

check...
7x - 3y = 45
7(-9/2) - 3(-153/6) = 45
-63/2 + 459/6 = 45 (multiply the equation by 6)
-189 + 459 = 270
270 = 270 (correct)

x = -9/2
y = -153/6