2+y=9 3x-7y=3 solve the system by the substitution

80/3 or 26 2/3

Step-by-step explanation:

-2 + y = 9 (subtract y from both sides)

-2 = 9 - y (subtract 9 from both sides)

-2 - 9 = y (multiply both sides by -1)

2 + 9 = y (simplify)

11 = y (substitute)

3x - 7 (11) = 3 (multiply)

3x - 77 = 3 (subtract 3 from both sides)

3x - 80 = 0 (subtract 3x from both sides)

-80 = -3x (multiply both sides by -1)

80 = 3x (divide both sides by 3)

80/3 = x (simplify if needed)

26 2/3 = x

a

b

d

step-by-step explanation:

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225