~~F.2Maths X2

1.
Put x=0, y=5 into the equation, we have
5 = a(0) + b
b = 5
Put x=2, y=0 into the equation, we have
0 = a(2) + 5
a = -5/2 = -2.5

Therefore, a = -2.5, b = 5

2.
Let the coordinates of A be (m,0) and coordinates of B be (0,n)
Then,
4(m) - (0) - 3 = 0
m = 3/4
4(0) - (n) - 3 = 0
n = -3

Therefore, m = 3/4, n = -3

1. If P(0,5) and Q(2,0) both lie on the graph of y=ax+b, find the values of a and b.

Sub. the P(0,5) into equation,
5=a(0)+b
b=5

Sub. the Q(2,0) into equation,
0=2a+5
a=-5/2

Thus,a=-5/2 and b=5

2.If the graph of 4x-y-3=0 intersects the x-axis and the y-axis at points A and B respectively, find the coordinates of A and B.

Sub the x-axis into the equation,
4x-0-3=0
x=3/4

Sub the y-axis into the equation,
4(0)-y-3=0
y=-3

Thus, the the coordinates of A and B are (3/4, 0) and (0, -3) respectively