You know that:y=ax^2+b

Subtract ax^2 from both sides to get:y-ax^2=b

Now substitute to get the two equations below:

b=5-a1^2=5-1a=5-a

and

b=11-a2^2=11-4a

Obviouslyb=b

So substitute to get:5-a=11-4a

subtract 5 from both sides:-a=6-4a

add 4a to both sides:3a=6

divide by 3:a=2

Now go back to equation:y=ax^2+b

Substitute:5=(2)(1)^2+b

thus:5=2+b

then:3=b

Now check:

y=ax^2+b

y=2x^2+3

y=2(2)^2+3

y=2(4)+3

y=8+3

y=11

So you can see it works. Can you do the other one?