Question

1)Write three solutions each for the following equations: - (i) 2x+ 3y=12 (ii) 5x-y= 10 2) If (3, -2) is a solution of the equation 3x − 2ky = 5, find ‘k’ 3) Write the coordinates of the point at which the line 4x − 7y = 8 intersect at x – axis. 4) Write equation of the line passing through (2,-3) and parallel to y- axis. 5) If (1,-2) is a solution of the equation 2x-y=p, then find the value of ‘p’.

Answer 1

cosA=5/13

sinA=-√(1-cos^2A) (since theta is in 4th quadrant)

i.e. sinA=-√144/169

=-12/13

tanB=-15/8

sinB=+(15)/√{(-15)^2+(8)^2} (B is in Q2)

i.e. sinB=15/17

cosB=tanB/sinB

i.e. cosB=-15/8 * 17/15

cosB=17/8

now

sin(A+B)=sinAcosB+cosAsinB

sin(A+B)=(-12/13)(17/8)+(5/13)(15/17)

={1/13}(-51/2 + 75/17)

=(1/13)(-710/34)

=-710/442