Tommy bought a total of 30 apples and oranges for a classic picnic. Apple's cost $3 per pound and oranges cost $4 per pound. Tommy spent $100 total. How many apples and oranges did Tommy buy? Please show work and explain

Solution: (20,10) Tommy bought 20 apples and 10 oranges.

Step-by-step explanation:

x+y=30: y=30-x

3x+4y=100

3x+4(30-x)=100

3x+120-4x=100

-1x +120=100

     -120   -120

-1x=-20

/-1   -1

x= 20

20+y= 30

-20     -20

y=10

20+10=30

You solve this equation using substitution

the polynomial is a perfect square trinomial of the form a^2-2ab+b^2:

option a. true

step-by-step explanation:

9x^2-12x+4

comparing with the form a^2-2ab+b^2

1.) a^2=9x^2

solving for a: square root both sides of the equation:

sqrt(a^2)=sqrt(9x^2)

a=sqrt(9) sqrt(x^2)

a=3x

2.) b^2=4

solving for b: square root both sides of the equation:

sqrt(b^2)=sqrt(4)

b=2

to be a perfet square trinomial 2ab must be equal to 12x. let's check:

2ab = 2 (3x) (2)

2ab = 12x

correct

step-by-step explanation:

your answer is a