Question

Solve the simultaneous equations:

y=3x+5
y=4x²+x
Give your answer correct to 2 decimal places

Answer 1

The solutions (x, y) are (1.40, 9.19) and (-0.90, 2.32) correct to 2 decimal places.

Explanation:

As the 2 expressions in x are both equal to y we can write:

4x^2 + x = 3x + 5

4x^2 - 2x - 5 = 0

x = [ -(-2) +/- sqrt(4 - 4*4*-5)] / 2*4

= 0.25 +/- (sqrt 84)/8

x = 1.396, -0.895.

When x = 1.396, y = 3(1.396) + 5 = 9.188

when x = 0.895, y = 3(-0.895) + 5 = 2.315.

Answer 2

Answer:answer to the questions are x=1.396 or -0.896 and y=9.188 or 2.312

Step-by-step explanation: see attachment

Thanks for drawing my attention to my mistake. I appreciate.