The sum of a number and 8 equal to 15

y - 8 = 15
5 + 7 = 8
x + 8 = 15

Leslie started last week with $1200 in her checking account. during the week, she wrote the checks below.

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b

Jeremy wants to determine the number of solutions for the equation below without actually solving the equation. which method should jeremy use?