Question

if the points a(3,5) and b(1,4) lie on the graph of the line ax + by=7. therefore, x=3,y=5 and x=1,y=4 are solutions of the equation ax+by=7​

Answer 1

Answer:

a=-1

b=2

Step-by-step explanation:

if x=3, y=5 then

3a+5b=7

if x=1, y=4 then

a+4b=7

so

3a+5b=7

a+4b=7   |*3⇒ 3a+12b=21

so

3a+12b=21

3a+5b=7

which means that 7b=21-7=14, so 7b=14⇒ b=2

a+4b=7 ⇔ a+4*2=7 ⇒ a=7-8 ⇒ a=-1