Hi! Love your book so far. I just started reviewing. I looked at number 10 in the first section on page 29 and I was wondering how would you pick the correct answer if you chose to substitute 8 for d? Because both answer choices a and d work. Would you just try all the answer choices and choose different variable values and try again or is there a different way to approach it?
4x + y = 7
2x – 7y = 1
If I multiply the second equation by 2, I can stack them and subtract:
4x + y = 7
4x – 14y = 2
So, 15y = 5, —> y = 3
Then: 2x – 7(3) = 1 –> 2x – 21 = 3 —> 2x = 24 –> x = 12
But: 4x + 3 = 7 –> 4x = 4 –> x = 1
What am I not seeing? The answer should be x= 5/3.
y -x =2 and y + x= -2 ,Then ( x+y)(x-y)=?
Test 9 Section 4 Question 16
Test 9 Section 4 Question 15
Hi Mike… can you work through the steps to solve Q 24 from Official Test 9 Section 4? thanks!
Hi Mike… can you solve this and explain please? Thanks!
ax + 5y = 8
12x + 15y = 10
In the given system of equations, a is a constant. If the system has no solutions, what is the value of a ?