You would multiply by

.
When you rationalize the denominator, you multiply by the conjugate of the denominator. The conjugate is the same numbers and radicals, but with the sign of the radical switched.
-3(b - 7)
Multiply -3 into the parenthesis.
= -3b + 21.
So, 30% is 0.30, but since you are taking off 30%, you are going to have 70% of the price which is 0.70. The word "of" lets you know that you are going to multiply. So, what you do is 150•0.70=105. The discounted price is $105
Solving inequalities is just like solving any other Algebraic problem...look to P.E.M.D.A.S. (Parenthesis, Exponents, Division, Addition, Subtraction). So lets take a look at this problem now.
1200 + 0.075x

3300
Subtract 1200 from both sides...
0.075x

2100
Now divide by 0.075...
x

28000
NOTE: If you divide or multiple by a negative number while solving inequalities, you must flip the sign. Ex: You answer would be x

28000 if you would've multiplied or divided by a negative.
Answer:
y = -2x + 6
Step-by-step explanation:
y=mx + c
m is the gradient and c is the y intercept
m = (y 2 - y 1) / (x 2 - x 1) = (2-4) / ( 2-1) = -2
y= -2x + c
To find c, just sub one of the coordinates into the eqn:
By using the coordinates (1,4)
4 = -2(1) + c
c = 6
Therefore, the equation is y = -2x + 6