Solve the simultaneous equations 3x + 2y = -7 and x=4y+21
Substitute in the second equation into the first to eliminate x from the first equation. Solve for y which should, when solved (shown below), equal -5. Sub -5 back into either equation in the place of y to then solve for x (shown below) x should then equal 1.
3(4y+21) +2y = -7 (solve for y)y = -53x +2(-5) = -7 (solve for x)x = 1
JG
Related Maths GCSE answers
All answers ▸What's the inverse of the function f=x+2?
Mark wants to borrow money to buy a car. His bank offers him a loan of £5,000 to be payed back over 3 years at 4% compound interest. a) Work out the interest acquired in the 2nd year. b) In total how much will Mark end up paying back the bank?
Find the values of x for the equation: x^2 - 8x = 105
f(x) = 5x − 12. (i) Calculate f(4). (ii) Find f( x + 1). Give your answer in the form ax + b .