4y = 2y + 40 4y - 2y = 2y -2y +40 2y = 40 y = 20 check 4(20) = 2(20) +40 80 = 80
x2 + y2 - 10x + 4y - 52 = 0 x2 - 10x + y2 + 4y = 52 Complete the square (x2 - 10x + 25) + (y2 + 4y + 4) = 52 + 25 + 4 (x - 5)2 + (y + 2)2 = 81 (x - 5)2 + (y - -2)2 = 92 This is the equation of a circle with center (5, -2), and radius 9.
2x + 4y = 12 ie 4y = 12 - 2x so y = 3 - x/2 Test: take x as 8 so y = -1: 2 x 8 + 4 x -1 does indeed = 12.
3x - 2y + 7x + 4y = 3x + 7x - 2y +4y = (3+7)x + (-2+4)y = 10x + 2y
2x + 6y = 93x - 12y = 15Chose the second equation because you can simplify it.3x - 12y = 15 divide by 3 to both sidesx - 4y = 5 add 4y to both sidesx = 4y + 5Replace 4y + 5 for x to the first equation.2x + 6y = 92(4y + 5) + 6y = 98y + 10 + 6y = 914y = -1y = -1/14x = 4y + 5x = 4(-1/14) + 5x = -2/7 + 5x = -2/7 + 35/7x = 33/7
4y+2 = 2y+6 4y-2y = 6-2 2y = 4 y = 2
It is an equation.
6x = 32 - 4y and 4y - 8 = 6x so 32 - 4y = 4y - 8 ie 40 = 8y so y = 5 and x = 2
y=2
(2, -1)
Factor out a 2; so it is 2(x+2y).
7(3y-2)-(-4y+9)
(4, -2)
(-1,-2)
y= 3/6 which reduces to 1/2
Yes.
By definition: 4y-2 = 6y+8 4y-6y = 8+2 -2y = 10 y = -5 and by substituting this value into the equation x = -22