What is the y intercept of 3x + 2y =21?

Answer 1

Put the equation into slope/intercept form:

y = mx + b

where b is the y-intercept.

Thus you have to solve for y.

3x + 2y = 21
2y = -3x + 21
y = -3/2x + 21/2

y-intercept = 21/2

Answer 2

If X=2 the Y is equal to:

3X + 2Y = 21
3(2) +2Y = 21
6 +2Y = 21
2Y = 21-6
2Y = 15
Y = 15/2
y = 7.5

Check: Substitution
3X + 2Y = 21
3(2)+2(7.5)=21
6 +15 =21

Conclusion:

If x=2 then y is equal to 7.5

Rules:

In substitution method, assign a number for one of the variables and substitute and the result of the other unknown variable.

You can be confident that your answers would be the right one by substituting, and if the answer corresponds, it is the right answer.

Answer 3

Putting the equation into y=mx +c gives you
y = -(3/2)x + (21/2) which means c=(21/2) where c=y-intercept

Putting the equation into intercept form gives you
(x/7) + (2y/21) = 1 => (x/7) + [y/(21/2)] = 1---------(*)
General intercept form is (x/a) + (y/b) =1 where b=y-intercept
So, from (*), y-intercept is 21/2 (same as first method)

Answer 4

for y intercept x = 0

putting x = 0 we get 2y = 21 or y = 21/2

Answer 5

FOR Y INTERCEPT, X=0,
SO, Y=21/2

Answer 6

3x + 2y =21
2y = 21 - 3x
y = - 3x / 2 + 21 / 2 .
The y intercept is 21 / 2.

Answer 7

21/2

Answer 8

2y = -3x + 21
y = (-3/2)x + 21/2

The y intercept is 21/2

Answer 9

3x + 2y =21 (change to slope-intercept form - y=mx+b)
3x + 2y - 3x = 21 - 3x
2y = 21 - 3x
y = (21 - 3x)/2
y = 10.5 - 1.5x
y = -1.5x + 10.5
slope = b = 10.5

(note that 21/2 & 10.5 are the same #)