SAT math
posted by mysterychicken on .
1. x>152x / 3 Solve the linear inequality. Write the solution in set builder notation.
So, 3x>152x, x<15..?
And how do I write it in set builder notation?
2. y+x=9 and 3y=2x + 8. How do I solve this system of equations?
3. Find the maximum y value of the following quadratic function: f(x)= 2x^2 + 7x + 1
4. Solve the following equation: 4x/3 + 1/2 = 5y/6
I'm not even sure what this question is asking...
5. Find the solution set to the equation below: 2*absolute value of x100 = 50 +absolute value of x100.
x = 150?

x > (152x)/3
looks like you multiplied both sides by 3, but did not reverse the inequality sign.
should have been:
3x < 15  2x
x < 15
x> 15
{x  x > 15 }
2. I would use substitution.
from the first: y =9x
sub into the 2nd:
3(9x) = 2x+8
27  3x = 2x + 8
5x = 19
x = 19/5 = 3.8
y = 93.8 = 5.2 
3. Find the maximum y value of the following quadratic function: f(x)= 2x^2 + 7x + 1
The maximum value of the y value is obtained from the vertex
the x of the vertex is b/(2a) = 7/4 = 7/4
y = 2(49/16) + 7(7/4) + 1 = 57/8
4.
4x/3 + 1/2 = 5y/6
multiply each term by 6
8x + 3 = 5y
8x + 5y + 3 = 0
> the equation of a straight line, with slope of 5/3
"solve" is not the correct instruction for this equation.
5.
2x100 = 50 + x100
2(x100) = 50 + x100 OR 2(x100) = 50 + x100
case1 :
2(x100) = 50 + x100
2x  200 = 50 + x100
2x  250 = x100
x100 = 2x250 OR x100 = 2x + 250
x = 150 OR 3x = 350
x = 150 OR x = 350/3
case2:
2(x100) = 50 + x100
2x + 10050 = x100
2x + 50 = x100
x100 = 2x + 50 OR x100 = 2x  50
3x = 150 OR x = 50
x = 50 or x = 50
x = ±50 , 150 , 350/3
check my arithmetic on the last one