21.0k views
1 vote
Solve
Y=4x-7
Y=x^2-2x+2

1 Answer

4 votes

Answer:

x = 3, y = 5

Explanation:

y =4x - 7

y = x² -2x + 2

so 4x - 7 = x² -2x + 2

subtract 4x from both sides and add 7 to both sides:

0 = x² -2x + 2 - 4x + 7

x² -6x + 9 = 0.

use the quadratic formula (can also factorise or complete the square):

x = ((-b ± √(b² - 4ac)) ÷ 2a)

where a is the value of the first coefficient, b is value of the second and c is value of the constant.

NB number in front of x ² is just one. When no number is presented in front, it is just a 1. In this case, it is 1 x ² (simply just one lot of x ², or just x ²).

x = [(-b ± √(b² - 4ac)) ÷ 2a]

a = 1, b = -6, c = 9.

x = [(-(-6) ± √((-6)² - 4(1)(9))) ÷ 2(1)]

= [(6 ± √(36 - 36)) ÷ 2]

= [(6 ± 0) ÷ 2]

= 3.

there are two roots, 3. why only 3? because 3 is a 'repeated root.' it's repeated, so there are two roots.

(x - 3) (x - 3) = x² - 3x - 3x + 3X3

= x² - 6x + 9 (exactly the equation we began with).

y = 4x - 7

= 4(3) - 7

= 12 - 7

= 5.

so, x = 3 and y = 5

User DimonZa
by
7.9k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories