Problem: If 8⋅2x=5y+88 \cdot 2^{x}=5^{y+8}8⋅2x=5y+8, then, when y=−8,x=y=-8, x=y=−8,x=
Answer Choices:
A. −4-4−4
B. −3-3−3
C. 000
D. 444
E. 888 Solution:
8â‹…2x=50;∴23+x=50=1;∴3+x=08 \cdot 2^{x}=5^{0} ; \quad \therefore 2^{3+x}=5^{0}=1 ; \quad \therefore 3+x=08â‹…2x=50;∴23+x=50=1;∴3+x=0 and x=−3x=-3x=−3. Note: 20=502^{0}=5^{0}20=50, but, otherwise, 2a≠5a2^{a} \neq 5^{a}2aî€ =5a.