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:

step-by-step explanation:

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