The equation for slope is y=mx+b therefore your equation would be y=.5x+2 or y=1/2+2
both of these are correct just the matter of fact of what way your teacher wants you to use :)
Multiply .03 by 42
.03×42=1.26
1.26kg + 42kg= 43.26
Answer: 43.26kg
Remember that a quadratic equation is a parabola. The equation is of the type y = Ax^2 + Bx + C
A linear equation is a straight line. The equation is of the type y = MX + N
The soluction of that system is Ax^2 + Bx + C = MX + N
=> Ax^2 + (B-M)x + (C-N) = 0
That is a quadratic equation.
A quadratic equation may have 0, 1 or 2 real solutions. Those are all the possibilitis.
So you must select 0, 1 and 2.
You can also get to that conclusion if you draw a parabola and figure out now many point of it you can intersect with a straight line.
You will realize that depending of the straight line position it can intersect the parabola in none point, or one point or two points.
Your choice of answer D is correct.
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When the number of days is zero, the height is 130 inches. This eliminates choices B and C. Evaluating the expression for n=13 gives
... 130 + 13×13 = 130 + 169 = 299 . . . . . corresponding to answer D.