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1. Can someone please help me with my maths homework?

1) An object is in equilibrium under the action of forces 3i + 5j, 2xi - yj, and 4i - 3j. Find x and y.

2) If:
a = xi + 3j
b = 2i - 8j
c = 4i - yj,
find x and y given that a + 2b = 3c

Thanks
2. (Original post by WoodenSword47)

1) An object is in equilibrium under the action of forces 3i + 5j, 2xi - yj, and 4i - 3j. Find x and y.

2) If:
a = xi + 3j
b = 2i - 8j
c = 4i - yj,
find x and y given that a + 2b = 3c

Thanks
What have you tried?
3. (Original post by WoodenSword47)

1) An object is in equilibrium under the action of forces 3i + 5j, 2xi - yj, and 4i - 3j. Find x and y.

2) If:
a = xi + 3j
b = 2i - 8j
c = 4i - yj,
find x and y given that a + 2b = 3c

Thanks
For 1) simply resolve in the i direction and in the j direction, since you're given that it's in equilibrium.
For 2) surely you can do a+2b=3c? Then it's just a case of comparing i and j coefficients; note that in any equation involving i and j unit vectors the coefficients of i and j on each side of the equation will match up.
4. (Original post by IrrationalRoot)
For 1) simply resolve in the i direction and in the j direction, since you're given that it's in equilibrium.
For 2) surely you can do a+2b=3c? Then it's just a case of comparing i and j coefficients; note that in any equation involving i and j unit vectors the coefficients of i and j on each side of the equation will match up.
Yeah, I've got it now. Thanks

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