Mallorie has $3 in her wallet. if this is 10% of her monthly allowance, what is her monthly allowance?

Her monthly allowance is 30 dollars

Mallorie's monthly allowance would be $30. 
  X represents the unknown value of the monthly allowance.  therefore, we can use the cross multiplying method to multiply 100 and 3 because 100 is the total value of the monthly allowance and we divide by 10 to get us a result of 30.  

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!