Help please asap 15,17,18 confused and honestly dont know

15. the x & y intercepts of an equations is zero

17.  a + b =120

b=120 - a

a - b =140

a - (120 - a) = 140

2a - 120 = 140

2a = 260

a = 130

b = 120 - a

b = 120 - 130

b = -10

18.exponents when multiplying numbers with the same base, you subtract the exponents when dividing numbers with the same base. Any number to the power of zero equals 1, as long as the base number is not 0.

Step-by-step explanation:

(x3 + 6x2 + 2x - 6) • (x - 1)

step-by-step explanation:

polynomial long division :

3.2     polynomial long division

dividing :   x4+5x3-4x2-8x+6

                              ("dividend")

by         :     x-1     ("divisor")

dividend     x4   +   5x3   -   4x2   -   8x   +   6

- divisor   * x3     x4   -   x3            

remainder         6x3   -   4x2   -   8x   +   6

- divisor   * 6x2         6x3   -   6x2        

remainder             2x2   -   8x   +   6

- divisor   * 2x1             2x2   -   2x    

remainder               -   6x   +   6

- divisor   * -6x0               -   6x   +   6

remainder                     0

quotient :   x3+6x2+2x-6   remainder:   0