Answer:
84°
Step-by-step explanation:
1. <u>point of intersection of 2y=x-13 and 3y+x+12=0</u>
x = 2y + 13 ==> 3y + (2y+13) + 12 = 0 ==> 5y + 25 = 0 ==> y = -5
x = 2*(-5) +13 = 3
point of intersection: (3 , -5) L1: pass (3 , -5) and (-4 , -7)
slope of L1 = (-7 - -5)/(-4-3) = -2 / -7 = 2/7
L2 pass (3 , -5) perpendicular to 2x-5y=4
2x-5y=4 ==> y = 2/5 x - 4 slope = 2/5
so slope of L2 = -5/2
angle Θ between two slopes: tan Θ = | (m2-m1) / (1 + m1*m2)|
==> = | (-5/2 - 2/7) / (1 + -5/2*2/7) | = |(-39/14) / (4/14) | = |- 39/4| = 39/4 = 9.75
Θ = 84°
