Norachai was going to sell all of his stamp collection to buy a video game. After
selling half of them he changed his mind.
He then bought seven more. How many did
he start with if he now has 25?

Subtract by seven, multiply by 2: 25-7=18 x 2=36

Abit confused about what you mean, but i think you might be referring to slope intercept form: y = mx + bin that case b, or the y intercept is already given.(0,-1)find the slope by using the formulay2 - y1/x2 - x1the final slope will be 4/2, equivalent to 2.now your equation should look like thisy = 4/2x -1sorry if this didn’t you out!