What is the value of a in the equation 5a-10b=45 when b=3

Since b = 3 the equation changes

5a - 10(3) = 45
5a - 30 = 45

(Add 30 to both sides)
5a = 75
Divide 5 to both sides
a = 15

If you would like to solve the equation 5 * a - 10 * b = 45, when b = 3, you can calculate this using the following steps:

b = 3
5 * a - 10 * b = 45
5 * a - 10 * 3 = 45
5 * a - 30 = 45
5 * a = 45 + 30
5 * a = 75       /5
a = 75 / 5
a = 15

Result: The value of a is 15.

the image of (6, 9) under a dilation is (4, 6). the scale factor is

b. 2/3