3: A 300g box of breakfast cereal costs £1.40. Work
out the cost of a 450g box of the cereal.

£2.10 should be right but it is rounded up

Line A.

Step-by-step explanation:

When you put x as zero into 3x-2, you get 3(0)-2. That equals -2. Therefore, y = -2. When x=0, that is the y-intercept, so the y-intercept is -2. Line A crosses the y-axis at -2, so line A has that y-intercept.

Slope is always y/x. On a graph, that is the number of squares UP over the number of squares ACROSS. Counting, we get, 3 squares up over 1 square across for line A. 3/1= 3. The slope is the number we multiply by x. In the equation, that is 3, because we see 3x, and no sign or space between 2 numbers automatically means we multiply. So line A also has the correct slope.

In linear equations (straight lines), the same slope and y-intercept are enough to tell you that the equation matches the line.

Therefore, the answer is A!